9f6a67ba17
--HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401209
3506 lines
117 KiB
C
3506 lines
117 KiB
C
/*
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** 2001 September 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This file contains C code routines that are called by the parser
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** to handle SELECT statements in SQLite.
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**
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** $Id$
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*/
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#include "sqliteInt.h"
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/*
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** Delete all the content of a Select structure but do not deallocate
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** the select structure itself.
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*/
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static void clearSelect(Select *p){
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sqlite3ExprListDelete(p->pEList);
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sqlite3SrcListDelete(p->pSrc);
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sqlite3ExprDelete(p->pWhere);
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sqlite3ExprListDelete(p->pGroupBy);
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sqlite3ExprDelete(p->pHaving);
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sqlite3ExprListDelete(p->pOrderBy);
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sqlite3SelectDelete(p->pPrior);
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sqlite3ExprDelete(p->pLimit);
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sqlite3ExprDelete(p->pOffset);
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}
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/*
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** Allocate a new Select structure and return a pointer to that
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** structure.
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*/
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Select *sqlite3SelectNew(
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ExprList *pEList, /* which columns to include in the result */
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SrcList *pSrc, /* the FROM clause -- which tables to scan */
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Expr *pWhere, /* the WHERE clause */
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ExprList *pGroupBy, /* the GROUP BY clause */
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Expr *pHaving, /* the HAVING clause */
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ExprList *pOrderBy, /* the ORDER BY clause */
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int isDistinct, /* true if the DISTINCT keyword is present */
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Expr *pLimit, /* LIMIT value. NULL means not used */
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Expr *pOffset /* OFFSET value. NULL means no offset */
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){
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Select *pNew;
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Select standin;
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pNew = sqliteMalloc( sizeof(*pNew) );
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assert( !pOffset || pLimit ); /* Can't have OFFSET without LIMIT. */
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if( pNew==0 ){
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pNew = &standin;
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memset(pNew, 0, sizeof(*pNew));
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}
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if( pEList==0 ){
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pEList = sqlite3ExprListAppend(0, sqlite3Expr(TK_ALL,0,0,0), 0);
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}
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pNew->pEList = pEList;
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pNew->pSrc = pSrc;
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pNew->pWhere = pWhere;
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pNew->pGroupBy = pGroupBy;
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pNew->pHaving = pHaving;
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pNew->pOrderBy = pOrderBy;
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pNew->isDistinct = isDistinct;
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pNew->op = TK_SELECT;
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assert( pOffset==0 || pLimit!=0 );
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pNew->pLimit = pLimit;
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pNew->pOffset = pOffset;
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pNew->iLimit = -1;
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pNew->iOffset = -1;
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pNew->addrOpenEphm[0] = -1;
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pNew->addrOpenEphm[1] = -1;
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pNew->addrOpenEphm[2] = -1;
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if( pNew==&standin) {
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clearSelect(pNew);
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pNew = 0;
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}
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return pNew;
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}
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/*
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** Delete the given Select structure and all of its substructures.
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*/
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void sqlite3SelectDelete(Select *p){
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if( p ){
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clearSelect(p);
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sqliteFree(p);
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}
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}
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/*
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** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
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** type of join. Return an integer constant that expresses that type
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** in terms of the following bit values:
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**
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** JT_INNER
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** JT_CROSS
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** JT_OUTER
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** JT_NATURAL
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** JT_LEFT
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** JT_RIGHT
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**
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** A full outer join is the combination of JT_LEFT and JT_RIGHT.
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**
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** If an illegal or unsupported join type is seen, then still return
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** a join type, but put an error in the pParse structure.
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*/
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int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
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int jointype = 0;
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Token *apAll[3];
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Token *p;
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static const struct {
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const char zKeyword[8];
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u8 nChar;
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u8 code;
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} keywords[] = {
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{ "natural", 7, JT_NATURAL },
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{ "left", 4, JT_LEFT|JT_OUTER },
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{ "right", 5, JT_RIGHT|JT_OUTER },
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{ "full", 4, JT_LEFT|JT_RIGHT|JT_OUTER },
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{ "outer", 5, JT_OUTER },
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{ "inner", 5, JT_INNER },
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{ "cross", 5, JT_INNER|JT_CROSS },
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};
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int i, j;
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apAll[0] = pA;
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apAll[1] = pB;
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apAll[2] = pC;
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for(i=0; i<3 && apAll[i]; i++){
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p = apAll[i];
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for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
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if( p->n==keywords[j].nChar
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&& sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
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jointype |= keywords[j].code;
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break;
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}
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}
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if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
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jointype |= JT_ERROR;
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break;
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}
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}
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if(
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(jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
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(jointype & JT_ERROR)!=0
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){
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const char *zSp1 = " ";
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const char *zSp2 = " ";
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if( pB==0 ){ zSp1++; }
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if( pC==0 ){ zSp2++; }
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sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
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"%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
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jointype = JT_INNER;
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}else if( jointype & JT_RIGHT ){
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sqlite3ErrorMsg(pParse,
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"RIGHT and FULL OUTER JOINs are not currently supported");
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jointype = JT_INNER;
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}
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return jointype;
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}
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/*
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** Return the index of a column in a table. Return -1 if the column
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** is not contained in the table.
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*/
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static int columnIndex(Table *pTab, const char *zCol){
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int i;
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for(i=0; i<pTab->nCol; i++){
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if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
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}
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return -1;
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}
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/*
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** Set the value of a token to a '\000'-terminated string.
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*/
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static void setToken(Token *p, const char *z){
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p->z = (u8*)z;
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p->n = z ? strlen(z) : 0;
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p->dyn = 0;
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}
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/*
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** Set the token to the double-quoted and escaped version of the string pointed
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** to by z. For example;
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**
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** {a"bc} -> {"a""bc"}
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*/
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static void setQuotedToken(Token *p, const char *z){
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p->z = (u8 *)sqlite3MPrintf("\"%w\"", z);
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p->dyn = 1;
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if( p->z ){
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p->n = strlen((char *)p->z);
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}
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}
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/*
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** Create an expression node for an identifier with the name of zName
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*/
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Expr *sqlite3CreateIdExpr(const char *zName){
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Token dummy;
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setToken(&dummy, zName);
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return sqlite3Expr(TK_ID, 0, 0, &dummy);
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}
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/*
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** Add a term to the WHERE expression in *ppExpr that requires the
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** zCol column to be equal in the two tables pTab1 and pTab2.
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*/
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static void addWhereTerm(
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const char *zCol, /* Name of the column */
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const Table *pTab1, /* First table */
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const char *zAlias1, /* Alias for first table. May be NULL */
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const Table *pTab2, /* Second table */
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const char *zAlias2, /* Alias for second table. May be NULL */
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int iRightJoinTable, /* VDBE cursor for the right table */
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Expr **ppExpr /* Add the equality term to this expression */
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){
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Expr *pE1a, *pE1b, *pE1c;
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Expr *pE2a, *pE2b, *pE2c;
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Expr *pE;
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pE1a = sqlite3CreateIdExpr(zCol);
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pE2a = sqlite3CreateIdExpr(zCol);
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if( zAlias1==0 ){
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zAlias1 = pTab1->zName;
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}
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pE1b = sqlite3CreateIdExpr(zAlias1);
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if( zAlias2==0 ){
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zAlias2 = pTab2->zName;
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}
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pE2b = sqlite3CreateIdExpr(zAlias2);
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pE1c = sqlite3ExprOrFree(TK_DOT, pE1b, pE1a, 0);
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pE2c = sqlite3ExprOrFree(TK_DOT, pE2b, pE2a, 0);
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pE = sqlite3ExprOrFree(TK_EQ, pE1c, pE2c, 0);
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if( pE ){
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ExprSetProperty(pE, EP_FromJoin);
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pE->iRightJoinTable = iRightJoinTable;
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}
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pE = sqlite3ExprAnd(*ppExpr, pE);
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if( pE ){
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*ppExpr = pE;
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}
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}
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/*
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** Set the EP_FromJoin property on all terms of the given expression.
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** And set the Expr.iRightJoinTable to iTable for every term in the
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** expression.
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**
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** The EP_FromJoin property is used on terms of an expression to tell
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** the LEFT OUTER JOIN processing logic that this term is part of the
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** join restriction specified in the ON or USING clause and not a part
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** of the more general WHERE clause. These terms are moved over to the
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** WHERE clause during join processing but we need to remember that they
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** originated in the ON or USING clause.
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**
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** The Expr.iRightJoinTable tells the WHERE clause processing that the
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** expression depends on table iRightJoinTable even if that table is not
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** explicitly mentioned in the expression. That information is needed
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** for cases like this:
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**
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** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
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**
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** The where clause needs to defer the handling of the t1.x=5
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** term until after the t2 loop of the join. In that way, a
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** NULL t2 row will be inserted whenever t1.x!=5. If we do not
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** defer the handling of t1.x=5, it will be processed immediately
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** after the t1 loop and rows with t1.x!=5 will never appear in
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** the output, which is incorrect.
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*/
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static void setJoinExpr(Expr *p, int iTable){
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while( p ){
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ExprSetProperty(p, EP_FromJoin);
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p->iRightJoinTable = iTable;
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setJoinExpr(p->pLeft, iTable);
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p = p->pRight;
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}
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}
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/*
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** This routine processes the join information for a SELECT statement.
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** ON and USING clauses are converted into extra terms of the WHERE clause.
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** NATURAL joins also create extra WHERE clause terms.
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**
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** The terms of a FROM clause are contained in the Select.pSrc structure.
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** The left most table is the first entry in Select.pSrc. The right-most
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** table is the last entry. The join operator is held in the entry to
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** the left. Thus entry 0 contains the join operator for the join between
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** entries 0 and 1. Any ON or USING clauses associated with the join are
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** also attached to the left entry.
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**
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** This routine returns the number of errors encountered.
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*/
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static int sqliteProcessJoin(Parse *pParse, Select *p){
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SrcList *pSrc; /* All tables in the FROM clause */
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int i, j; /* Loop counters */
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struct SrcList_item *pLeft; /* Left table being joined */
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struct SrcList_item *pRight; /* Right table being joined */
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pSrc = p->pSrc;
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pLeft = &pSrc->a[0];
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pRight = &pLeft[1];
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for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
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Table *pLeftTab = pLeft->pTab;
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Table *pRightTab = pRight->pTab;
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if( pLeftTab==0 || pRightTab==0 ) continue;
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/* When the NATURAL keyword is present, add WHERE clause terms for
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** every column that the two tables have in common.
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*/
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if( pRight->jointype & JT_NATURAL ){
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if( pRight->pOn || pRight->pUsing ){
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sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
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"an ON or USING clause", 0);
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return 1;
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}
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for(j=0; j<pLeftTab->nCol; j++){
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char *zName = pLeftTab->aCol[j].zName;
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if( columnIndex(pRightTab, zName)>=0 ){
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addWhereTerm(zName, pLeftTab, pLeft->zAlias,
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pRightTab, pRight->zAlias,
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pRight->iCursor, &p->pWhere);
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}
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}
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}
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/* Disallow both ON and USING clauses in the same join
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*/
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if( pRight->pOn && pRight->pUsing ){
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sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
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"clauses in the same join");
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return 1;
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}
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/* Add the ON clause to the end of the WHERE clause, connected by
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** an AND operator.
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*/
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if( pRight->pOn ){
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setJoinExpr(pRight->pOn, pRight->iCursor);
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p->pWhere = sqlite3ExprAnd(p->pWhere, pRight->pOn);
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pRight->pOn = 0;
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}
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/* Create extra terms on the WHERE clause for each column named
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** in the USING clause. Example: If the two tables to be joined are
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** A and B and the USING clause names X, Y, and Z, then add this
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** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
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** Report an error if any column mentioned in the USING clause is
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** not contained in both tables to be joined.
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*/
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if( pRight->pUsing ){
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IdList *pList = pRight->pUsing;
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for(j=0; j<pList->nId; j++){
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char *zName = pList->a[j].zName;
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if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
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sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
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"not present in both tables", zName);
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return 1;
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}
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addWhereTerm(zName, pLeftTab, pLeft->zAlias,
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pRightTab, pRight->zAlias,
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pRight->iCursor, &p->pWhere);
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}
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}
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}
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return 0;
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}
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/*
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** Insert code into "v" that will push the record on the top of the
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** stack into the sorter.
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*/
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static void pushOntoSorter(
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Parse *pParse, /* Parser context */
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ExprList *pOrderBy, /* The ORDER BY clause */
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Select *pSelect /* The whole SELECT statement */
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){
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Vdbe *v = pParse->pVdbe;
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sqlite3ExprCodeExprList(pParse, pOrderBy);
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sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
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sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
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sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
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sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
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if( pSelect->iLimit>=0 ){
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int addr1, addr2;
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addr1 = sqlite3VdbeAddOp(v, OP_IfMemZero, pSelect->iLimit+1, 0);
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sqlite3VdbeAddOp(v, OP_MemIncr, -1, pSelect->iLimit+1);
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addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
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sqlite3VdbeJumpHere(v, addr1);
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sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
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sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
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sqlite3VdbeJumpHere(v, addr2);
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pSelect->iLimit = -1;
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}
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}
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/*
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** Add code to implement the OFFSET
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*/
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static void codeOffset(
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Vdbe *v, /* Generate code into this VM */
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Select *p, /* The SELECT statement being coded */
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int iContinue, /* Jump here to skip the current record */
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int nPop /* Number of times to pop stack when jumping */
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){
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if( p->iOffset>=0 && iContinue!=0 ){
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int addr;
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sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
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addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, 0);
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if( nPop>0 ){
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sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
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}
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sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
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VdbeComment((v, "# skip OFFSET records"));
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sqlite3VdbeJumpHere(v, addr);
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}
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}
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/*
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** Add code that will check to make sure the top N elements of the
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** stack are distinct. iTab is a sorting index that holds previously
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** seen combinations of the N values. A new entry is made in iTab
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** if the current N values are new.
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**
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** A jump to addrRepeat is made and the N+1 values are popped from the
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** stack if the top N elements are not distinct.
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*/
|
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static void codeDistinct(
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Vdbe *v, /* Generate code into this VM */
|
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int iTab, /* A sorting index used to test for distinctness */
|
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int addrRepeat, /* Jump to here if not distinct */
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int N /* The top N elements of the stack must be distinct */
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){
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sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
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sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
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sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
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sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
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VdbeComment((v, "# skip indistinct records"));
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sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
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}
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|
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/*
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** Generate an error message when a SELECT is used within a subexpression
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|
** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
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** column. We do this in a subroutine because the error occurs in multiple
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** places.
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*/
|
|
static int checkForMultiColumnSelectError(Parse *pParse, int eDest, int nExpr){
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if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
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sqlite3ErrorMsg(pParse, "only a single result allowed for "
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"a SELECT that is part of an expression");
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return 1;
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}else{
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return 0;
|
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}
|
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}
|
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|
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/*
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** This routine generates the code for the inside of the inner loop
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|
** of a SELECT.
|
|
**
|
|
** If srcTab and nColumn are both zero, then the pEList expressions
|
|
** are evaluated in order to get the data for this row. If nColumn>0
|
|
** then data is pulled from srcTab and pEList is used only to get the
|
|
** datatypes for each column.
|
|
*/
|
|
static int selectInnerLoop(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The complete select statement being coded */
|
|
ExprList *pEList, /* List of values being extracted */
|
|
int srcTab, /* Pull data from this table */
|
|
int nColumn, /* Number of columns in the source table */
|
|
ExprList *pOrderBy, /* If not NULL, sort results using this key */
|
|
int distinct, /* If >=0, make sure results are distinct */
|
|
int eDest, /* How to dispose of the results */
|
|
int iParm, /* An argument to the disposal method */
|
|
int iContinue, /* Jump here to continue with next row */
|
|
int iBreak, /* Jump here to break out of the inner loop */
|
|
char *aff /* affinity string if eDest is SRT_Union */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
int hasDistinct; /* True if the DISTINCT keyword is present */
|
|
|
|
if( v==0 ) return 0;
|
|
assert( pEList!=0 );
|
|
|
|
/* If there was a LIMIT clause on the SELECT statement, then do the check
|
|
** to see if this row should be output.
|
|
*/
|
|
hasDistinct = distinct>=0 && pEList->nExpr>0;
|
|
if( pOrderBy==0 && !hasDistinct ){
|
|
codeOffset(v, p, iContinue, 0);
|
|
}
|
|
|
|
/* Pull the requested columns.
|
|
*/
|
|
if( nColumn>0 ){
|
|
for(i=0; i<nColumn; i++){
|
|
sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
|
|
}
|
|
}else{
|
|
nColumn = pEList->nExpr;
|
|
sqlite3ExprCodeExprList(pParse, pEList);
|
|
}
|
|
|
|
/* If the DISTINCT keyword was present on the SELECT statement
|
|
** and this row has been seen before, then do not make this row
|
|
** part of the result.
|
|
*/
|
|
if( hasDistinct ){
|
|
assert( pEList!=0 );
|
|
assert( pEList->nExpr==nColumn );
|
|
codeDistinct(v, distinct, iContinue, nColumn);
|
|
if( pOrderBy==0 ){
|
|
codeOffset(v, p, iContinue, nColumn);
|
|
}
|
|
}
|
|
|
|
if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
|
|
return 0;
|
|
}
|
|
|
|
switch( eDest ){
|
|
/* In this mode, write each query result to the key of the temporary
|
|
** table iParm.
|
|
*/
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
case SRT_Union: {
|
|
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
if( aff ){
|
|
sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
|
|
break;
|
|
}
|
|
|
|
/* Construct a record from the query result, but instead of
|
|
** saving that record, use it as a key to delete elements from
|
|
** the temporary table iParm.
|
|
*/
|
|
case SRT_Except: {
|
|
int addr;
|
|
addr = sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
|
|
sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
|
|
sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
|
|
break;
|
|
}
|
|
#endif
|
|
|
|
/* Store the result as data using a unique key.
|
|
*/
|
|
case SRT_Table:
|
|
case SRT_EphemTab: {
|
|
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
if( pOrderBy ){
|
|
pushOntoSorter(pParse, pOrderBy, p);
|
|
}else{
|
|
sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
|
|
sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
|
|
sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
|
|
}
|
|
break;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
/* If we are creating a set for an "expr IN (SELECT ...)" construct,
|
|
** then there should be a single item on the stack. Write this
|
|
** item into the set table with bogus data.
|
|
*/
|
|
case SRT_Set: {
|
|
int addr1 = sqlite3VdbeCurrentAddr(v);
|
|
int addr2;
|
|
|
|
assert( nColumn==1 );
|
|
sqlite3VdbeAddOp(v, OP_NotNull, -1, addr1+3);
|
|
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
|
|
addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
|
|
p->affinity = sqlite3CompareAffinity(pEList->a[0].pExpr,(iParm>>16)&0xff);
|
|
if( pOrderBy ){
|
|
/* At first glance you would think we could optimize out the
|
|
** ORDER BY in this case since the order of entries in the set
|
|
** does not matter. But there might be a LIMIT clause, in which
|
|
** case the order does matter */
|
|
pushOntoSorter(pParse, pOrderBy, p);
|
|
}else{
|
|
sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
|
|
sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
|
|
}
|
|
sqlite3VdbeJumpHere(v, addr2);
|
|
break;
|
|
}
|
|
|
|
/* If any row exist in the result set, record that fact and abort.
|
|
*/
|
|
case SRT_Exists: {
|
|
sqlite3VdbeAddOp(v, OP_MemInt, 1, iParm);
|
|
sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
|
|
/* The LIMIT clause will terminate the loop for us */
|
|
break;
|
|
}
|
|
|
|
/* If this is a scalar select that is part of an expression, then
|
|
** store the results in the appropriate memory cell and break out
|
|
** of the scan loop.
|
|
*/
|
|
case SRT_Mem: {
|
|
assert( nColumn==1 );
|
|
if( pOrderBy ){
|
|
pushOntoSorter(pParse, pOrderBy, p);
|
|
}else{
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
/* The LIMIT clause will jump out of the loop for us */
|
|
}
|
|
break;
|
|
}
|
|
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
|
|
|
|
/* Send the data to the callback function or to a subroutine. In the
|
|
** case of a subroutine, the subroutine itself is responsible for
|
|
** popping the data from the stack.
|
|
*/
|
|
case SRT_Subroutine:
|
|
case SRT_Callback: {
|
|
if( pOrderBy ){
|
|
sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
|
|
pushOntoSorter(pParse, pOrderBy, p);
|
|
}else if( eDest==SRT_Subroutine ){
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
|
|
}else{
|
|
sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
|
|
}
|
|
break;
|
|
}
|
|
|
|
#if !defined(SQLITE_OMIT_TRIGGER)
|
|
/* Discard the results. This is used for SELECT statements inside
|
|
** the body of a TRIGGER. The purpose of such selects is to call
|
|
** user-defined functions that have side effects. We do not care
|
|
** about the actual results of the select.
|
|
*/
|
|
default: {
|
|
assert( eDest==SRT_Discard );
|
|
sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
|
|
break;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Jump to the end of the loop if the LIMIT is reached.
|
|
*/
|
|
if( p->iLimit>=0 && pOrderBy==0 ){
|
|
sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
|
|
sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, iBreak);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Given an expression list, generate a KeyInfo structure that records
|
|
** the collating sequence for each expression in that expression list.
|
|
**
|
|
** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
|
|
** KeyInfo structure is appropriate for initializing a virtual index to
|
|
** implement that clause. If the ExprList is the result set of a SELECT
|
|
** then the KeyInfo structure is appropriate for initializing a virtual
|
|
** index to implement a DISTINCT test.
|
|
**
|
|
** Space to hold the KeyInfo structure is obtain from malloc. The calling
|
|
** function is responsible for seeing that this structure is eventually
|
|
** freed. Add the KeyInfo structure to the P3 field of an opcode using
|
|
** P3_KEYINFO_HANDOFF is the usual way of dealing with this.
|
|
*/
|
|
static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
|
|
sqlite3 *db = pParse->db;
|
|
int nExpr;
|
|
KeyInfo *pInfo;
|
|
struct ExprList_item *pItem;
|
|
int i;
|
|
|
|
nExpr = pList->nExpr;
|
|
pInfo = sqliteMalloc( sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
|
|
if( pInfo ){
|
|
pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
|
|
pInfo->nField = nExpr;
|
|
pInfo->enc = ENC(db);
|
|
for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
|
|
CollSeq *pColl;
|
|
pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
|
|
if( !pColl ){
|
|
pColl = db->pDfltColl;
|
|
}
|
|
pInfo->aColl[i] = pColl;
|
|
pInfo->aSortOrder[i] = pItem->sortOrder;
|
|
}
|
|
}
|
|
return pInfo;
|
|
}
|
|
|
|
|
|
/*
|
|
** If the inner loop was generated using a non-null pOrderBy argument,
|
|
** then the results were placed in a sorter. After the loop is terminated
|
|
** we need to run the sorter and output the results. The following
|
|
** routine generates the code needed to do that.
|
|
*/
|
|
static void generateSortTail(
|
|
Parse *pParse, /* Parsing context */
|
|
Select *p, /* The SELECT statement */
|
|
Vdbe *v, /* Generate code into this VDBE */
|
|
int nColumn, /* Number of columns of data */
|
|
int eDest, /* Write the sorted results here */
|
|
int iParm /* Optional parameter associated with eDest */
|
|
){
|
|
int brk = sqlite3VdbeMakeLabel(v);
|
|
int cont = sqlite3VdbeMakeLabel(v);
|
|
int addr;
|
|
int iTab;
|
|
int pseudoTab = 0;
|
|
ExprList *pOrderBy = p->pOrderBy;
|
|
|
|
iTab = pOrderBy->iECursor;
|
|
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
|
|
pseudoTab = pParse->nTab++;
|
|
sqlite3VdbeAddOp(v, OP_OpenPseudo, pseudoTab, 0);
|
|
sqlite3VdbeAddOp(v, OP_SetNumColumns, pseudoTab, nColumn);
|
|
}
|
|
addr = 1 + sqlite3VdbeAddOp(v, OP_Sort, iTab, brk);
|
|
codeOffset(v, p, cont, 0);
|
|
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
|
|
sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_Column, iTab, pOrderBy->nExpr + 1);
|
|
switch( eDest ){
|
|
case SRT_Table:
|
|
case SRT_EphemTab: {
|
|
sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
|
|
sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
|
|
sqlite3VdbeAddOp(v, OP_Insert, iParm, OPFLAG_APPEND);
|
|
break;
|
|
}
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
case SRT_Set: {
|
|
assert( nColumn==1 );
|
|
sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
|
|
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqlite3VdbeAddOp(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
|
|
sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &p->affinity, 1);
|
|
sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
|
|
break;
|
|
}
|
|
case SRT_Mem: {
|
|
assert( nColumn==1 );
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
|
|
/* The LIMIT clause will terminate the loop for us */
|
|
break;
|
|
}
|
|
#endif
|
|
case SRT_Callback:
|
|
case SRT_Subroutine: {
|
|
int i;
|
|
sqlite3VdbeAddOp(v, OP_Insert, pseudoTab, 0);
|
|
for(i=0; i<nColumn; i++){
|
|
sqlite3VdbeAddOp(v, OP_Column, pseudoTab, i);
|
|
}
|
|
if( eDest==SRT_Callback ){
|
|
sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
|
|
}else{
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
|
|
}
|
|
break;
|
|
}
|
|
default: {
|
|
/* Do nothing */
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Jump to the end of the loop when the LIMIT is reached
|
|
*/
|
|
if( p->iLimit>=0 ){
|
|
sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
|
|
sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, brk);
|
|
}
|
|
|
|
/* The bottom of the loop
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, cont);
|
|
sqlite3VdbeAddOp(v, OP_Next, iTab, addr);
|
|
sqlite3VdbeResolveLabel(v, brk);
|
|
if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
|
|
sqlite3VdbeAddOp(v, OP_Close, pseudoTab, 0);
|
|
}
|
|
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to a string containing the 'declaration type' of the
|
|
** expression pExpr. The string may be treated as static by the caller.
|
|
**
|
|
** The declaration type is the exact datatype definition extracted from the
|
|
** original CREATE TABLE statement if the expression is a column. The
|
|
** declaration type for a ROWID field is INTEGER. Exactly when an expression
|
|
** is considered a column can be complex in the presence of subqueries. The
|
|
** result-set expression in all of the following SELECT statements is
|
|
** considered a column by this function.
|
|
**
|
|
** SELECT col FROM tbl;
|
|
** SELECT (SELECT col FROM tbl;
|
|
** SELECT (SELECT col FROM tbl);
|
|
** SELECT abc FROM (SELECT col AS abc FROM tbl);
|
|
**
|
|
** The declaration type for any expression other than a column is NULL.
|
|
*/
|
|
static const char *columnType(
|
|
NameContext *pNC,
|
|
Expr *pExpr,
|
|
const char **pzOriginDb,
|
|
const char **pzOriginTab,
|
|
const char **pzOriginCol
|
|
){
|
|
char const *zType = 0;
|
|
char const *zOriginDb = 0;
|
|
char const *zOriginTab = 0;
|
|
char const *zOriginCol = 0;
|
|
int j;
|
|
if( pExpr==0 || pNC->pSrcList==0 ) return 0;
|
|
|
|
switch( pExpr->op ){
|
|
case TK_AGG_COLUMN:
|
|
case TK_COLUMN: {
|
|
/* The expression is a column. Locate the table the column is being
|
|
** extracted from in NameContext.pSrcList. This table may be real
|
|
** database table or a subquery.
|
|
*/
|
|
Table *pTab = 0; /* Table structure column is extracted from */
|
|
Select *pS = 0; /* Select the column is extracted from */
|
|
int iCol = pExpr->iColumn; /* Index of column in pTab */
|
|
while( pNC && !pTab ){
|
|
SrcList *pTabList = pNC->pSrcList;
|
|
for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
|
|
if( j<pTabList->nSrc ){
|
|
pTab = pTabList->a[j].pTab;
|
|
pS = pTabList->a[j].pSelect;
|
|
}else{
|
|
pNC = pNC->pNext;
|
|
}
|
|
}
|
|
|
|
if( pTab==0 ){
|
|
/* FIX ME:
|
|
** This can occurs if you have something like "SELECT new.x;" inside
|
|
** a trigger. In other words, if you reference the special "new"
|
|
** table in the result set of a select. We do not have a good way
|
|
** to find the actual table type, so call it "TEXT". This is really
|
|
** something of a bug, but I do not know how to fix it.
|
|
**
|
|
** This code does not produce the correct answer - it just prevents
|
|
** a segfault. See ticket #1229.
|
|
*/
|
|
zType = "TEXT";
|
|
break;
|
|
}
|
|
|
|
assert( pTab );
|
|
if( pS ){
|
|
/* The "table" is actually a sub-select or a view in the FROM clause
|
|
** of the SELECT statement. Return the declaration type and origin
|
|
** data for the result-set column of the sub-select.
|
|
*/
|
|
if( iCol>=0 && iCol<pS->pEList->nExpr ){
|
|
/* If iCol is less than zero, then the expression requests the
|
|
** rowid of the sub-select or view. This expression is legal (see
|
|
** test case misc2.2.2) - it always evaluates to NULL.
|
|
*/
|
|
NameContext sNC;
|
|
Expr *p = pS->pEList->a[iCol].pExpr;
|
|
sNC.pSrcList = pS->pSrc;
|
|
sNC.pNext = 0;
|
|
sNC.pParse = pNC->pParse;
|
|
zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
|
|
}
|
|
}else if( pTab->pSchema ){
|
|
/* A real table */
|
|
assert( !pS );
|
|
if( iCol<0 ) iCol = pTab->iPKey;
|
|
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
|
if( iCol<0 ){
|
|
zType = "INTEGER";
|
|
zOriginCol = "rowid";
|
|
}else{
|
|
zType = pTab->aCol[iCol].zType;
|
|
zOriginCol = pTab->aCol[iCol].zName;
|
|
}
|
|
zOriginTab = pTab->zName;
|
|
if( pNC->pParse ){
|
|
int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
|
|
zOriginDb = pNC->pParse->db->aDb[iDb].zName;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
case TK_SELECT: {
|
|
/* The expression is a sub-select. Return the declaration type and
|
|
** origin info for the single column in the result set of the SELECT
|
|
** statement.
|
|
*/
|
|
NameContext sNC;
|
|
Select *pS = pExpr->pSelect;
|
|
Expr *p = pS->pEList->a[0].pExpr;
|
|
sNC.pSrcList = pS->pSrc;
|
|
sNC.pNext = pNC;
|
|
sNC.pParse = pNC->pParse;
|
|
zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol);
|
|
break;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
if( pzOriginDb ){
|
|
assert( pzOriginTab && pzOriginCol );
|
|
*pzOriginDb = zOriginDb;
|
|
*pzOriginTab = zOriginTab;
|
|
*pzOriginCol = zOriginCol;
|
|
}
|
|
return zType;
|
|
}
|
|
|
|
/*
|
|
** Generate code that will tell the VDBE the declaration types of columns
|
|
** in the result set.
|
|
*/
|
|
static void generateColumnTypes(
|
|
Parse *pParse, /* Parser context */
|
|
SrcList *pTabList, /* List of tables */
|
|
ExprList *pEList /* Expressions defining the result set */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
NameContext sNC;
|
|
sNC.pSrcList = pTabList;
|
|
sNC.pParse = pParse;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
Expr *p = pEList->a[i].pExpr;
|
|
const char *zOrigDb = 0;
|
|
const char *zOrigTab = 0;
|
|
const char *zOrigCol = 0;
|
|
const char *zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);
|
|
|
|
/* The vdbe must make it's own copy of the column-type and other
|
|
** column specific strings, in case the schema is reset before this
|
|
** virtual machine is deleted.
|
|
*/
|
|
sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P3_TRANSIENT);
|
|
sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P3_TRANSIENT);
|
|
sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P3_TRANSIENT);
|
|
sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P3_TRANSIENT);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Generate code that will tell the VDBE the names of columns
|
|
** in the result set. This information is used to provide the
|
|
** azCol[] values in the callback.
|
|
*/
|
|
static void generateColumnNames(
|
|
Parse *pParse, /* Parser context */
|
|
SrcList *pTabList, /* List of tables */
|
|
ExprList *pEList /* Expressions defining the result set */
|
|
){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i, j;
|
|
sqlite3 *db = pParse->db;
|
|
int fullNames, shortNames;
|
|
|
|
#ifndef SQLITE_OMIT_EXPLAIN
|
|
/* If this is an EXPLAIN, skip this step */
|
|
if( pParse->explain ){
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
assert( v!=0 );
|
|
if( pParse->colNamesSet || v==0 || sqlite3MallocFailed() ) return;
|
|
pParse->colNamesSet = 1;
|
|
fullNames = (db->flags & SQLITE_FullColNames)!=0;
|
|
shortNames = (db->flags & SQLITE_ShortColNames)!=0;
|
|
sqlite3VdbeSetNumCols(v, pEList->nExpr);
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
Expr *p;
|
|
p = pEList->a[i].pExpr;
|
|
if( p==0 ) continue;
|
|
if( pEList->a[i].zName ){
|
|
char *zName = pEList->a[i].zName;
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
|
|
continue;
|
|
}
|
|
if( p->op==TK_COLUMN && pTabList ){
|
|
Table *pTab;
|
|
char *zCol;
|
|
int iCol = p->iColumn;
|
|
for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
|
|
assert( j<pTabList->nSrc );
|
|
pTab = pTabList->a[j].pTab;
|
|
if( iCol<0 ) iCol = pTab->iPKey;
|
|
assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
|
|
if( iCol<0 ){
|
|
zCol = "rowid";
|
|
}else{
|
|
zCol = pTab->aCol[iCol].zName;
|
|
}
|
|
if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
|
|
}else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
|
|
char *zName = 0;
|
|
char *zTab;
|
|
|
|
zTab = pTabList->a[j].zAlias;
|
|
if( fullNames || zTab==0 ) zTab = pTab->zName;
|
|
sqlite3SetString(&zName, zTab, ".", zCol, (char*)0);
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P3_DYNAMIC);
|
|
}else{
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
|
|
}
|
|
}else if( p->span.z && p->span.z[0] ){
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
|
|
/* sqlite3VdbeCompressSpace(v, addr); */
|
|
}else{
|
|
char zName[30];
|
|
assert( p->op!=TK_COLUMN || pTabList==0 );
|
|
sqlite3_snprintf(sizeof(zName), zName, "column%d", i+1);
|
|
sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, 0);
|
|
}
|
|
}
|
|
generateColumnTypes(pParse, pTabList, pEList);
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
/*
|
|
** Name of the connection operator, used for error messages.
|
|
*/
|
|
static const char *selectOpName(int id){
|
|
char *z;
|
|
switch( id ){
|
|
case TK_ALL: z = "UNION ALL"; break;
|
|
case TK_INTERSECT: z = "INTERSECT"; break;
|
|
case TK_EXCEPT: z = "EXCEPT"; break;
|
|
default: z = "UNION"; break;
|
|
}
|
|
return z;
|
|
}
|
|
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
|
|
|
/*
|
|
** Forward declaration
|
|
*/
|
|
static int prepSelectStmt(Parse*, Select*);
|
|
|
|
/*
|
|
** Given a SELECT statement, generate a Table structure that describes
|
|
** the result set of that SELECT.
|
|
*/
|
|
Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
|
|
Table *pTab;
|
|
int i, j;
|
|
ExprList *pEList;
|
|
Column *aCol, *pCol;
|
|
|
|
while( pSelect->pPrior ) pSelect = pSelect->pPrior;
|
|
if( prepSelectStmt(pParse, pSelect) ){
|
|
return 0;
|
|
}
|
|
if( sqlite3SelectResolve(pParse, pSelect, 0) ){
|
|
return 0;
|
|
}
|
|
pTab = sqliteMalloc( sizeof(Table) );
|
|
if( pTab==0 ){
|
|
return 0;
|
|
}
|
|
pTab->nRef = 1;
|
|
pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
|
|
pEList = pSelect->pEList;
|
|
pTab->nCol = pEList->nExpr;
|
|
assert( pTab->nCol>0 );
|
|
pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
|
|
for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
|
|
Expr *p, *pR;
|
|
char *zType;
|
|
char *zName;
|
|
int nName;
|
|
CollSeq *pColl;
|
|
int cnt;
|
|
NameContext sNC;
|
|
|
|
/* Get an appropriate name for the column
|
|
*/
|
|
p = pEList->a[i].pExpr;
|
|
assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
|
|
if( (zName = pEList->a[i].zName)!=0 ){
|
|
/* If the column contains an "AS <name>" phrase, use <name> as the name */
|
|
zName = sqliteStrDup(zName);
|
|
}else if( p->op==TK_DOT
|
|
&& (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
|
|
/* For columns of the from A.B use B as the name */
|
|
zName = sqlite3MPrintf("%T", &pR->token);
|
|
}else if( p->span.z && p->span.z[0] ){
|
|
/* Use the original text of the column expression as its name */
|
|
zName = sqlite3MPrintf("%T", &p->span);
|
|
}else{
|
|
/* If all else fails, make up a name */
|
|
zName = sqlite3MPrintf("column%d", i+1);
|
|
}
|
|
sqlite3Dequote(zName);
|
|
if( sqlite3MallocFailed() ){
|
|
sqliteFree(zName);
|
|
sqlite3DeleteTable(pTab);
|
|
return 0;
|
|
}
|
|
|
|
/* Make sure the column name is unique. If the name is not unique,
|
|
** append a integer to the name so that it becomes unique.
|
|
*/
|
|
nName = strlen(zName);
|
|
for(j=cnt=0; j<i; j++){
|
|
if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
|
|
zName[nName] = 0;
|
|
zName = sqlite3MPrintf("%z:%d", zName, ++cnt);
|
|
j = -1;
|
|
if( zName==0 ) break;
|
|
}
|
|
}
|
|
pCol->zName = zName;
|
|
|
|
/* Get the typename, type affinity, and collating sequence for the
|
|
** column.
|
|
*/
|
|
memset(&sNC, 0, sizeof(sNC));
|
|
sNC.pSrcList = pSelect->pSrc;
|
|
zType = sqliteStrDup(columnType(&sNC, p, 0, 0, 0));
|
|
pCol->zType = zType;
|
|
pCol->affinity = sqlite3ExprAffinity(p);
|
|
pColl = sqlite3ExprCollSeq(pParse, p);
|
|
if( pColl ){
|
|
pCol->zColl = sqliteStrDup(pColl->zName);
|
|
}
|
|
}
|
|
pTab->iPKey = -1;
|
|
return pTab;
|
|
}
|
|
|
|
/*
|
|
** Prepare a SELECT statement for processing by doing the following
|
|
** things:
|
|
**
|
|
** (1) Make sure VDBE cursor numbers have been assigned to every
|
|
** element of the FROM clause.
|
|
**
|
|
** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
|
|
** defines FROM clause. When views appear in the FROM clause,
|
|
** fill pTabList->a[].pSelect with a copy of the SELECT statement
|
|
** that implements the view. A copy is made of the view's SELECT
|
|
** statement so that we can freely modify or delete that statement
|
|
** without worrying about messing up the presistent representation
|
|
** of the view.
|
|
**
|
|
** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
|
|
** on joins and the ON and USING clause of joins.
|
|
**
|
|
** (4) Scan the list of columns in the result set (pEList) looking
|
|
** for instances of the "*" operator or the TABLE.* operator.
|
|
** If found, expand each "*" to be every column in every table
|
|
** and TABLE.* to be every column in TABLE.
|
|
**
|
|
** Return 0 on success. If there are problems, leave an error message
|
|
** in pParse and return non-zero.
|
|
*/
|
|
static int prepSelectStmt(Parse *pParse, Select *p){
|
|
int i, j, k, rc;
|
|
SrcList *pTabList;
|
|
ExprList *pEList;
|
|
struct SrcList_item *pFrom;
|
|
|
|
if( p==0 || p->pSrc==0 || sqlite3MallocFailed() ){
|
|
return 1;
|
|
}
|
|
pTabList = p->pSrc;
|
|
pEList = p->pEList;
|
|
|
|
/* Make sure cursor numbers have been assigned to all entries in
|
|
** the FROM clause of the SELECT statement.
|
|
*/
|
|
sqlite3SrcListAssignCursors(pParse, p->pSrc);
|
|
|
|
/* Look up every table named in the FROM clause of the select. If
|
|
** an entry of the FROM clause is a subquery instead of a table or view,
|
|
** then create a transient table structure to describe the subquery.
|
|
*/
|
|
for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
|
|
Table *pTab;
|
|
if( pFrom->pTab!=0 ){
|
|
/* This statement has already been prepared. There is no need
|
|
** to go further. */
|
|
assert( i==0 );
|
|
return 0;
|
|
}
|
|
if( pFrom->zName==0 ){
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
/* A sub-query in the FROM clause of a SELECT */
|
|
assert( pFrom->pSelect!=0 );
|
|
if( pFrom->zAlias==0 ){
|
|
pFrom->zAlias =
|
|
sqlite3MPrintf("sqlite_subquery_%p_", (void*)pFrom->pSelect);
|
|
}
|
|
assert( pFrom->pTab==0 );
|
|
pFrom->pTab = pTab =
|
|
sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
|
|
if( pTab==0 ){
|
|
return 1;
|
|
}
|
|
/* The isEphem flag indicates that the Table structure has been
|
|
** dynamically allocated and may be freed at any time. In other words,
|
|
** pTab is not pointing to a persistent table structure that defines
|
|
** part of the schema. */
|
|
pTab->isEphem = 1;
|
|
#endif
|
|
}else{
|
|
/* An ordinary table or view name in the FROM clause */
|
|
assert( pFrom->pTab==0 );
|
|
pFrom->pTab = pTab =
|
|
sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
|
|
if( pTab==0 ){
|
|
return 1;
|
|
}
|
|
pTab->nRef++;
|
|
#if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
|
|
if( pTab->pSelect || IsVirtual(pTab) ){
|
|
/* We reach here if the named table is a really a view */
|
|
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
|
|
return 1;
|
|
}
|
|
/* If pFrom->pSelect!=0 it means we are dealing with a
|
|
** view within a view. The SELECT structure has already been
|
|
** copied by the outer view so we can skip the copy step here
|
|
** in the inner view.
|
|
*/
|
|
if( pFrom->pSelect==0 ){
|
|
pFrom->pSelect = sqlite3SelectDup(pTab->pSelect);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* Process NATURAL keywords, and ON and USING clauses of joins.
|
|
*/
|
|
if( sqliteProcessJoin(pParse, p) ) return 1;
|
|
|
|
/* For every "*" that occurs in the column list, insert the names of
|
|
** all columns in all tables. And for every TABLE.* insert the names
|
|
** of all columns in TABLE. The parser inserted a special expression
|
|
** with the TK_ALL operator for each "*" that it found in the column list.
|
|
** The following code just has to locate the TK_ALL expressions and expand
|
|
** each one to the list of all columns in all tables.
|
|
**
|
|
** The first loop just checks to see if there are any "*" operators
|
|
** that need expanding.
|
|
*/
|
|
for(k=0; k<pEList->nExpr; k++){
|
|
Expr *pE = pEList->a[k].pExpr;
|
|
if( pE->op==TK_ALL ) break;
|
|
if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
|
|
&& pE->pLeft && pE->pLeft->op==TK_ID ) break;
|
|
}
|
|
rc = 0;
|
|
if( k<pEList->nExpr ){
|
|
/*
|
|
** If we get here it means the result set contains one or more "*"
|
|
** operators that need to be expanded. Loop through each expression
|
|
** in the result set and expand them one by one.
|
|
*/
|
|
struct ExprList_item *a = pEList->a;
|
|
ExprList *pNew = 0;
|
|
int flags = pParse->db->flags;
|
|
int longNames = (flags & SQLITE_FullColNames)!=0 &&
|
|
(flags & SQLITE_ShortColNames)==0;
|
|
|
|
for(k=0; k<pEList->nExpr; k++){
|
|
Expr *pE = a[k].pExpr;
|
|
if( pE->op!=TK_ALL &&
|
|
(pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
|
|
/* This particular expression does not need to be expanded.
|
|
*/
|
|
pNew = sqlite3ExprListAppend(pNew, a[k].pExpr, 0);
|
|
if( pNew ){
|
|
pNew->a[pNew->nExpr-1].zName = a[k].zName;
|
|
}else{
|
|
rc = 1;
|
|
}
|
|
a[k].pExpr = 0;
|
|
a[k].zName = 0;
|
|
}else{
|
|
/* This expression is a "*" or a "TABLE.*" and needs to be
|
|
** expanded. */
|
|
int tableSeen = 0; /* Set to 1 when TABLE matches */
|
|
char *zTName; /* text of name of TABLE */
|
|
if( pE->op==TK_DOT && pE->pLeft ){
|
|
zTName = sqlite3NameFromToken(&pE->pLeft->token);
|
|
}else{
|
|
zTName = 0;
|
|
}
|
|
for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
|
|
Table *pTab = pFrom->pTab;
|
|
char *zTabName = pFrom->zAlias;
|
|
if( zTabName==0 || zTabName[0]==0 ){
|
|
zTabName = pTab->zName;
|
|
}
|
|
if( zTName && (zTabName==0 || zTabName[0]==0 ||
|
|
sqlite3StrICmp(zTName, zTabName)!=0) ){
|
|
continue;
|
|
}
|
|
tableSeen = 1;
|
|
for(j=0; j<pTab->nCol; j++){
|
|
Expr *pExpr, *pRight;
|
|
char *zName = pTab->aCol[j].zName;
|
|
|
|
/* If a column is marked as 'hidden' (currently only possible
|
|
** for virtual tables), do not include it in the expanded
|
|
** result-set list.
|
|
*/
|
|
if( IsHiddenColumn(&pTab->aCol[j]) ){
|
|
assert(IsVirtual(pTab));
|
|
continue;
|
|
}
|
|
|
|
if( i>0 ){
|
|
struct SrcList_item *pLeft = &pTabList->a[i-1];
|
|
if( (pLeft[1].jointype & JT_NATURAL)!=0 &&
|
|
columnIndex(pLeft->pTab, zName)>=0 ){
|
|
/* In a NATURAL join, omit the join columns from the
|
|
** table on the right */
|
|
continue;
|
|
}
|
|
if( sqlite3IdListIndex(pLeft[1].pUsing, zName)>=0 ){
|
|
/* In a join with a USING clause, omit columns in the
|
|
** using clause from the table on the right. */
|
|
continue;
|
|
}
|
|
}
|
|
pRight = sqlite3Expr(TK_ID, 0, 0, 0);
|
|
if( pRight==0 ) break;
|
|
setQuotedToken(&pRight->token, zName);
|
|
if( zTabName && (longNames || pTabList->nSrc>1) ){
|
|
Expr *pLeft = sqlite3Expr(TK_ID, 0, 0, 0);
|
|
pExpr = sqlite3Expr(TK_DOT, pLeft, pRight, 0);
|
|
if( pExpr==0 ) break;
|
|
setQuotedToken(&pLeft->token, zTabName);
|
|
setToken(&pExpr->span, sqlite3MPrintf("%s.%s", zTabName, zName));
|
|
pExpr->span.dyn = 1;
|
|
pExpr->token.z = 0;
|
|
pExpr->token.n = 0;
|
|
pExpr->token.dyn = 0;
|
|
}else{
|
|
pExpr = pRight;
|
|
pExpr->span = pExpr->token;
|
|
pExpr->span.dyn = 0;
|
|
}
|
|
if( longNames ){
|
|
pNew = sqlite3ExprListAppend(pNew, pExpr, &pExpr->span);
|
|
}else{
|
|
pNew = sqlite3ExprListAppend(pNew, pExpr, &pRight->token);
|
|
}
|
|
}
|
|
}
|
|
if( !tableSeen ){
|
|
if( zTName ){
|
|
sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
|
|
}else{
|
|
sqlite3ErrorMsg(pParse, "no tables specified");
|
|
}
|
|
rc = 1;
|
|
}
|
|
sqliteFree(zTName);
|
|
}
|
|
}
|
|
sqlite3ExprListDelete(pEList);
|
|
p->pEList = pNew;
|
|
}
|
|
if( p->pEList && p->pEList->nExpr>SQLITE_MAX_COLUMN ){
|
|
sqlite3ErrorMsg(pParse, "too many columns in result set");
|
|
rc = SQLITE_ERROR;
|
|
}
|
|
if( sqlite3MallocFailed() ){
|
|
rc = SQLITE_NOMEM;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
/*
|
|
** This routine associates entries in an ORDER BY expression list with
|
|
** columns in a result. For each ORDER BY expression, the opcode of
|
|
** the top-level node is changed to TK_COLUMN and the iColumn value of
|
|
** the top-level node is filled in with column number and the iTable
|
|
** value of the top-level node is filled with iTable parameter.
|
|
**
|
|
** If there are prior SELECT clauses, they are processed first. A match
|
|
** in an earlier SELECT takes precedence over a later SELECT.
|
|
**
|
|
** Any entry that does not match is flagged as an error. The number
|
|
** of errors is returned.
|
|
*/
|
|
static int matchOrderbyToColumn(
|
|
Parse *pParse, /* A place to leave error messages */
|
|
Select *pSelect, /* Match to result columns of this SELECT */
|
|
ExprList *pOrderBy, /* The ORDER BY values to match against columns */
|
|
int iTable, /* Insert this value in iTable */
|
|
int mustComplete /* If TRUE all ORDER BYs must match */
|
|
){
|
|
int nErr = 0;
|
|
int i, j;
|
|
ExprList *pEList;
|
|
|
|
if( pSelect==0 || pOrderBy==0 ) return 1;
|
|
if( mustComplete ){
|
|
for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
|
|
}
|
|
if( prepSelectStmt(pParse, pSelect) ){
|
|
return 1;
|
|
}
|
|
if( pSelect->pPrior ){
|
|
if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
|
|
return 1;
|
|
}
|
|
}
|
|
pEList = pSelect->pEList;
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
struct ExprList_item *pItem;
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
int iCol = -1;
|
|
char *zLabel;
|
|
|
|
if( pOrderBy->a[i].done ) continue;
|
|
if( sqlite3ExprIsInteger(pE, &iCol) ){
|
|
if( iCol<=0 || iCol>pEList->nExpr ){
|
|
sqlite3ErrorMsg(pParse,
|
|
"ORDER BY position %d should be between 1 and %d",
|
|
iCol, pEList->nExpr);
|
|
nErr++;
|
|
break;
|
|
}
|
|
if( !mustComplete ) continue;
|
|
iCol--;
|
|
}
|
|
if( iCol<0 && (zLabel = sqlite3NameFromToken(&pE->token))!=0 ){
|
|
for(j=0, pItem=pEList->a; j<pEList->nExpr; j++, pItem++){
|
|
char *zName;
|
|
int isMatch;
|
|
if( pItem->zName ){
|
|
zName = sqlite3StrDup(pItem->zName);
|
|
}else{
|
|
zName = sqlite3NameFromToken(&pItem->pExpr->token);
|
|
}
|
|
isMatch = zName && sqlite3StrICmp(zName, zLabel)==0;
|
|
sqliteFree(zName);
|
|
if( isMatch ){
|
|
iCol = j;
|
|
break;
|
|
}
|
|
}
|
|
sqliteFree(zLabel);
|
|
}
|
|
if( iCol>=0 ){
|
|
pE->op = TK_COLUMN;
|
|
pE->iColumn = iCol;
|
|
pE->iTable = iTable;
|
|
pE->iAgg = -1;
|
|
pOrderBy->a[i].done = 1;
|
|
}else if( mustComplete ){
|
|
sqlite3ErrorMsg(pParse,
|
|
"ORDER BY term number %d does not match any result column", i+1);
|
|
nErr++;
|
|
break;
|
|
}
|
|
}
|
|
return nErr;
|
|
}
|
|
#endif /* #ifndef SQLITE_OMIT_COMPOUND_SELECT */
|
|
|
|
/*
|
|
** Get a VDBE for the given parser context. Create a new one if necessary.
|
|
** If an error occurs, return NULL and leave a message in pParse.
|
|
*/
|
|
Vdbe *sqlite3GetVdbe(Parse *pParse){
|
|
Vdbe *v = pParse->pVdbe;
|
|
if( v==0 ){
|
|
v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
|
|
}
|
|
return v;
|
|
}
|
|
|
|
|
|
/*
|
|
** Compute the iLimit and iOffset fields of the SELECT based on the
|
|
** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
|
|
** that appear in the original SQL statement after the LIMIT and OFFSET
|
|
** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
|
|
** are the integer memory register numbers for counters used to compute
|
|
** the limit and offset. If there is no limit and/or offset, then
|
|
** iLimit and iOffset are negative.
|
|
**
|
|
** This routine changes the values of iLimit and iOffset only if
|
|
** a limit or offset is defined by pLimit and pOffset. iLimit and
|
|
** iOffset should have been preset to appropriate default values
|
|
** (usually but not always -1) prior to calling this routine.
|
|
** Only if pLimit!=0 or pOffset!=0 do the limit registers get
|
|
** redefined. The UNION ALL operator uses this property to force
|
|
** the reuse of the same limit and offset registers across multiple
|
|
** SELECT statements.
|
|
*/
|
|
static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
|
|
Vdbe *v = 0;
|
|
int iLimit = 0;
|
|
int iOffset;
|
|
int addr1, addr2;
|
|
|
|
/*
|
|
** "LIMIT -1" always shows all rows. There is some
|
|
** contraversy about what the correct behavior should be.
|
|
** The current implementation interprets "LIMIT 0" to mean
|
|
** no rows.
|
|
*/
|
|
if( p->pLimit ){
|
|
p->iLimit = iLimit = pParse->nMem;
|
|
pParse->nMem += 2;
|
|
v = sqlite3GetVdbe(pParse);
|
|
if( v==0 ) return;
|
|
sqlite3ExprCode(pParse, p->pLimit);
|
|
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 1);
|
|
VdbeComment((v, "# LIMIT counter"));
|
|
sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
|
|
sqlite3VdbeAddOp(v, OP_MemLoad, iLimit, 0);
|
|
}
|
|
if( p->pOffset ){
|
|
p->iOffset = iOffset = pParse->nMem++;
|
|
v = sqlite3GetVdbe(pParse);
|
|
if( v==0 ) return;
|
|
sqlite3ExprCode(pParse, p->pOffset);
|
|
sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
|
|
VdbeComment((v, "# OFFSET counter"));
|
|
addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
|
|
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
|
|
sqlite3VdbeJumpHere(v, addr1);
|
|
if( p->pLimit ){
|
|
sqlite3VdbeAddOp(v, OP_Add, 0, 0);
|
|
}
|
|
}
|
|
if( p->pLimit ){
|
|
addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
|
|
sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
|
|
sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
|
|
addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
|
|
sqlite3VdbeJumpHere(v, addr1);
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
|
|
VdbeComment((v, "# LIMIT+OFFSET"));
|
|
sqlite3VdbeJumpHere(v, addr2);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Allocate a virtual index to use for sorting.
|
|
*/
|
|
static void createSortingIndex(Parse *pParse, Select *p, ExprList *pOrderBy){
|
|
if( pOrderBy ){
|
|
int addr;
|
|
assert( pOrderBy->iECursor==0 );
|
|
pOrderBy->iECursor = pParse->nTab++;
|
|
addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenEphemeral,
|
|
pOrderBy->iECursor, pOrderBy->nExpr+1);
|
|
assert( p->addrOpenEphm[2] == -1 );
|
|
p->addrOpenEphm[2] = addr;
|
|
}
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
/*
|
|
** Return the appropriate collating sequence for the iCol-th column of
|
|
** the result set for the compound-select statement "p". Return NULL if
|
|
** the column has no default collating sequence.
|
|
**
|
|
** The collating sequence for the compound select is taken from the
|
|
** left-most term of the select that has a collating sequence.
|
|
*/
|
|
static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
|
|
CollSeq *pRet;
|
|
if( p->pPrior ){
|
|
pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
|
|
}else{
|
|
pRet = 0;
|
|
}
|
|
if( pRet==0 ){
|
|
pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
|
|
}
|
|
return pRet;
|
|
}
|
|
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
|
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
/*
|
|
** This routine is called to process a query that is really the union
|
|
** or intersection of two or more separate queries.
|
|
**
|
|
** "p" points to the right-most of the two queries. the query on the
|
|
** left is p->pPrior. The left query could also be a compound query
|
|
** in which case this routine will be called recursively.
|
|
**
|
|
** The results of the total query are to be written into a destination
|
|
** of type eDest with parameter iParm.
|
|
**
|
|
** Example 1: Consider a three-way compound SQL statement.
|
|
**
|
|
** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
|
|
**
|
|
** This statement is parsed up as follows:
|
|
**
|
|
** SELECT c FROM t3
|
|
** |
|
|
** `-----> SELECT b FROM t2
|
|
** |
|
|
** `------> SELECT a FROM t1
|
|
**
|
|
** The arrows in the diagram above represent the Select.pPrior pointer.
|
|
** So if this routine is called with p equal to the t3 query, then
|
|
** pPrior will be the t2 query. p->op will be TK_UNION in this case.
|
|
**
|
|
** Notice that because of the way SQLite parses compound SELECTs, the
|
|
** individual selects always group from left to right.
|
|
*/
|
|
static int multiSelect(
|
|
Parse *pParse, /* Parsing context */
|
|
Select *p, /* The right-most of SELECTs to be coded */
|
|
int eDest, /* \___ Store query results as specified */
|
|
int iParm, /* / by these two parameters. */
|
|
char *aff /* If eDest is SRT_Union, the affinity string */
|
|
){
|
|
int rc = SQLITE_OK; /* Success code from a subroutine */
|
|
Select *pPrior; /* Another SELECT immediately to our left */
|
|
Vdbe *v; /* Generate code to this VDBE */
|
|
int nCol; /* Number of columns in the result set */
|
|
ExprList *pOrderBy; /* The ORDER BY clause on p */
|
|
int aSetP2[2]; /* Set P2 value of these op to number of columns */
|
|
int nSetP2 = 0; /* Number of slots in aSetP2[] used */
|
|
|
|
/* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
|
|
** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
|
|
*/
|
|
if( p==0 || p->pPrior==0 ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
pPrior = p->pPrior;
|
|
assert( pPrior->pRightmost!=pPrior );
|
|
assert( pPrior->pRightmost==p->pRightmost );
|
|
if( pPrior->pOrderBy ){
|
|
sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
|
|
selectOpName(p->op));
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
if( pPrior->pLimit ){
|
|
sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
|
|
selectOpName(p->op));
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Make sure we have a valid query engine. If not, create a new one.
|
|
*/
|
|
v = sqlite3GetVdbe(pParse);
|
|
if( v==0 ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Create the destination temporary table if necessary
|
|
*/
|
|
if( eDest==SRT_EphemTab ){
|
|
assert( p->pEList );
|
|
assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
|
|
aSetP2[nSetP2++] = sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 0);
|
|
eDest = SRT_Table;
|
|
}
|
|
|
|
/* Generate code for the left and right SELECT statements.
|
|
*/
|
|
pOrderBy = p->pOrderBy;
|
|
switch( p->op ){
|
|
case TK_ALL: {
|
|
if( pOrderBy==0 ){
|
|
int addr = 0;
|
|
assert( !pPrior->pLimit );
|
|
pPrior->pLimit = p->pLimit;
|
|
pPrior->pOffset = p->pOffset;
|
|
rc = sqlite3Select(pParse, pPrior, eDest, iParm, 0, 0, 0, aff);
|
|
p->pLimit = 0;
|
|
p->pOffset = 0;
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
p->pPrior = 0;
|
|
p->iLimit = pPrior->iLimit;
|
|
p->iOffset = pPrior->iOffset;
|
|
if( p->iLimit>=0 ){
|
|
addr = sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, 0);
|
|
VdbeComment((v, "# Jump ahead if LIMIT reached"));
|
|
}
|
|
rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
|
|
p->pPrior = pPrior;
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
if( addr ){
|
|
sqlite3VdbeJumpHere(v, addr);
|
|
}
|
|
break;
|
|
}
|
|
/* For UNION ALL ... ORDER BY fall through to the next case */
|
|
}
|
|
case TK_EXCEPT:
|
|
case TK_UNION: {
|
|
int unionTab; /* Cursor number of the temporary table holding result */
|
|
int op = 0; /* One of the SRT_ operations to apply to self */
|
|
int priorOp; /* The SRT_ operation to apply to prior selects */
|
|
Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
|
|
int addr;
|
|
|
|
priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
|
|
if( eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
|
|
/* We can reuse a temporary table generated by a SELECT to our
|
|
** right.
|
|
*/
|
|
unionTab = iParm;
|
|
}else{
|
|
/* We will need to create our own temporary table to hold the
|
|
** intermediate results.
|
|
*/
|
|
unionTab = pParse->nTab++;
|
|
if( pOrderBy && matchOrderbyToColumn(pParse, p, pOrderBy, unionTab,1) ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, unionTab, 0);
|
|
if( priorOp==SRT_Table ){
|
|
assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
|
|
aSetP2[nSetP2++] = addr;
|
|
}else{
|
|
assert( p->addrOpenEphm[0] == -1 );
|
|
p->addrOpenEphm[0] = addr;
|
|
p->pRightmost->usesEphm = 1;
|
|
}
|
|
createSortingIndex(pParse, p, pOrderBy);
|
|
assert( p->pEList );
|
|
}
|
|
|
|
/* Code the SELECT statements to our left
|
|
*/
|
|
assert( !pPrior->pOrderBy );
|
|
rc = sqlite3Select(pParse, pPrior, priorOp, unionTab, 0, 0, 0, aff);
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Code the current SELECT statement
|
|
*/
|
|
switch( p->op ){
|
|
case TK_EXCEPT: op = SRT_Except; break;
|
|
case TK_UNION: op = SRT_Union; break;
|
|
case TK_ALL: op = SRT_Table; break;
|
|
}
|
|
p->pPrior = 0;
|
|
p->pOrderBy = 0;
|
|
p->disallowOrderBy = pOrderBy!=0;
|
|
pLimit = p->pLimit;
|
|
p->pLimit = 0;
|
|
pOffset = p->pOffset;
|
|
p->pOffset = 0;
|
|
rc = sqlite3Select(pParse, p, op, unionTab, 0, 0, 0, aff);
|
|
/* Query flattening in sqlite3Select() might refill p->pOrderBy.
|
|
** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
|
|
sqlite3ExprListDelete(p->pOrderBy);
|
|
p->pPrior = pPrior;
|
|
p->pOrderBy = pOrderBy;
|
|
sqlite3ExprDelete(p->pLimit);
|
|
p->pLimit = pLimit;
|
|
p->pOffset = pOffset;
|
|
p->iLimit = -1;
|
|
p->iOffset = -1;
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
|
|
|
|
/* Convert the data in the temporary table into whatever form
|
|
** it is that we currently need.
|
|
*/
|
|
if( eDest!=priorOp || unionTab!=iParm ){
|
|
int iCont, iBreak, iStart;
|
|
assert( p->pEList );
|
|
if( eDest==SRT_Callback ){
|
|
Select *pFirst = p;
|
|
while( pFirst->pPrior ) pFirst = pFirst->pPrior;
|
|
generateColumnNames(pParse, 0, pFirst->pEList);
|
|
}
|
|
iBreak = sqlite3VdbeMakeLabel(v);
|
|
iCont = sqlite3VdbeMakeLabel(v);
|
|
computeLimitRegisters(pParse, p, iBreak);
|
|
sqlite3VdbeAddOp(v, OP_Rewind, unionTab, iBreak);
|
|
iStart = sqlite3VdbeCurrentAddr(v);
|
|
rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
|
|
pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak, 0);
|
|
if( rc ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
sqlite3VdbeResolveLabel(v, iCont);
|
|
sqlite3VdbeAddOp(v, OP_Next, unionTab, iStart);
|
|
sqlite3VdbeResolveLabel(v, iBreak);
|
|
sqlite3VdbeAddOp(v, OP_Close, unionTab, 0);
|
|
}
|
|
break;
|
|
}
|
|
case TK_INTERSECT: {
|
|
int tab1, tab2;
|
|
int iCont, iBreak, iStart;
|
|
Expr *pLimit, *pOffset;
|
|
int addr;
|
|
|
|
/* INTERSECT is different from the others since it requires
|
|
** two temporary tables. Hence it has its own case. Begin
|
|
** by allocating the tables we will need.
|
|
*/
|
|
tab1 = pParse->nTab++;
|
|
tab2 = pParse->nTab++;
|
|
if( pOrderBy && matchOrderbyToColumn(pParse,p,pOrderBy,tab1,1) ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
createSortingIndex(pParse, p, pOrderBy);
|
|
|
|
addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, tab1, 0);
|
|
assert( p->addrOpenEphm[0] == -1 );
|
|
p->addrOpenEphm[0] = addr;
|
|
p->pRightmost->usesEphm = 1;
|
|
assert( p->pEList );
|
|
|
|
/* Code the SELECTs to our left into temporary table "tab1".
|
|
*/
|
|
rc = sqlite3Select(pParse, pPrior, SRT_Union, tab1, 0, 0, 0, aff);
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Code the current SELECT into temporary table "tab2"
|
|
*/
|
|
addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, tab2, 0);
|
|
assert( p->addrOpenEphm[1] == -1 );
|
|
p->addrOpenEphm[1] = addr;
|
|
p->pPrior = 0;
|
|
pLimit = p->pLimit;
|
|
p->pLimit = 0;
|
|
pOffset = p->pOffset;
|
|
p->pOffset = 0;
|
|
rc = sqlite3Select(pParse, p, SRT_Union, tab2, 0, 0, 0, aff);
|
|
p->pPrior = pPrior;
|
|
sqlite3ExprDelete(p->pLimit);
|
|
p->pLimit = pLimit;
|
|
p->pOffset = pOffset;
|
|
if( rc ){
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Generate code to take the intersection of the two temporary
|
|
** tables.
|
|
*/
|
|
assert( p->pEList );
|
|
if( eDest==SRT_Callback ){
|
|
Select *pFirst = p;
|
|
while( pFirst->pPrior ) pFirst = pFirst->pPrior;
|
|
generateColumnNames(pParse, 0, pFirst->pEList);
|
|
}
|
|
iBreak = sqlite3VdbeMakeLabel(v);
|
|
iCont = sqlite3VdbeMakeLabel(v);
|
|
computeLimitRegisters(pParse, p, iBreak);
|
|
sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
|
|
iStart = sqlite3VdbeAddOp(v, OP_RowKey, tab1, 0);
|
|
sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
|
|
rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
|
|
pOrderBy, -1, eDest, iParm,
|
|
iCont, iBreak, 0);
|
|
if( rc ){
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
sqlite3VdbeResolveLabel(v, iCont);
|
|
sqlite3VdbeAddOp(v, OP_Next, tab1, iStart);
|
|
sqlite3VdbeResolveLabel(v, iBreak);
|
|
sqlite3VdbeAddOp(v, OP_Close, tab2, 0);
|
|
sqlite3VdbeAddOp(v, OP_Close, tab1, 0);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Make sure all SELECTs in the statement have the same number of elements
|
|
** in their result sets.
|
|
*/
|
|
assert( p->pEList && pPrior->pEList );
|
|
if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
|
|
sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
|
|
" do not have the same number of result columns", selectOpName(p->op));
|
|
rc = 1;
|
|
goto multi_select_end;
|
|
}
|
|
|
|
/* Set the number of columns in temporary tables
|
|
*/
|
|
nCol = p->pEList->nExpr;
|
|
while( nSetP2 ){
|
|
sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
|
|
}
|
|
|
|
/* Compute collating sequences used by either the ORDER BY clause or
|
|
** by any temporary tables needed to implement the compound select.
|
|
** Attach the KeyInfo structure to all temporary tables. Invoke the
|
|
** ORDER BY processing if there is an ORDER BY clause.
|
|
**
|
|
** This section is run by the right-most SELECT statement only.
|
|
** SELECT statements to the left always skip this part. The right-most
|
|
** SELECT might also skip this part if it has no ORDER BY clause and
|
|
** no temp tables are required.
|
|
*/
|
|
if( pOrderBy || p->usesEphm ){
|
|
int i; /* Loop counter */
|
|
KeyInfo *pKeyInfo; /* Collating sequence for the result set */
|
|
Select *pLoop; /* For looping through SELECT statements */
|
|
int nKeyCol; /* Number of entries in pKeyInfo->aCol[] */
|
|
CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
|
|
CollSeq **aCopy; /* A copy of pKeyInfo->aColl[] */
|
|
|
|
assert( p->pRightmost==p );
|
|
nKeyCol = nCol + (pOrderBy ? pOrderBy->nExpr : 0);
|
|
pKeyInfo = sqliteMalloc(sizeof(*pKeyInfo)+nKeyCol*(sizeof(CollSeq*) + 1));
|
|
if( !pKeyInfo ){
|
|
rc = SQLITE_NOMEM;
|
|
goto multi_select_end;
|
|
}
|
|
|
|
pKeyInfo->enc = ENC(pParse->db);
|
|
pKeyInfo->nField = nCol;
|
|
|
|
for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
|
|
*apColl = multiSelectCollSeq(pParse, p, i);
|
|
if( 0==*apColl ){
|
|
*apColl = pParse->db->pDfltColl;
|
|
}
|
|
}
|
|
|
|
for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
|
|
for(i=0; i<2; i++){
|
|
int addr = pLoop->addrOpenEphm[i];
|
|
if( addr<0 ){
|
|
/* If [0] is unused then [1] is also unused. So we can
|
|
** always safely abort as soon as the first unused slot is found */
|
|
assert( pLoop->addrOpenEphm[1]<0 );
|
|
break;
|
|
}
|
|
sqlite3VdbeChangeP2(v, addr, nCol);
|
|
sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO);
|
|
pLoop->addrOpenEphm[i] = -1;
|
|
}
|
|
}
|
|
|
|
if( pOrderBy ){
|
|
struct ExprList_item *pOTerm = pOrderBy->a;
|
|
int nOrderByExpr = pOrderBy->nExpr;
|
|
int addr;
|
|
u8 *pSortOrder;
|
|
|
|
/* Reuse the same pKeyInfo for the ORDER BY as was used above for
|
|
** the compound select statements. Except we have to change out the
|
|
** pKeyInfo->aColl[] values. Some of the aColl[] values will be
|
|
** reused when constructing the pKeyInfo for the ORDER BY, so make
|
|
** a copy. Sufficient space to hold both the nCol entries for
|
|
** the compound select and the nOrderbyExpr entries for the ORDER BY
|
|
** was allocated above. But we need to move the compound select
|
|
** entries out of the way before constructing the ORDER BY entries.
|
|
** Move the compound select entries into aCopy[] where they can be
|
|
** accessed and reused when constructing the ORDER BY entries.
|
|
** Because nCol might be greater than or less than nOrderByExpr
|
|
** we have to use memmove() when doing the copy.
|
|
*/
|
|
aCopy = &pKeyInfo->aColl[nOrderByExpr];
|
|
pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
|
|
memmove(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));
|
|
|
|
apColl = pKeyInfo->aColl;
|
|
for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
|
|
Expr *pExpr = pOTerm->pExpr;
|
|
if( (pExpr->flags & EP_ExpCollate) ){
|
|
assert( pExpr->pColl!=0 );
|
|
*apColl = pExpr->pColl;
|
|
}else{
|
|
*apColl = aCopy[pExpr->iColumn];
|
|
}
|
|
*pSortOrder = pOTerm->sortOrder;
|
|
}
|
|
assert( p->pRightmost==p );
|
|
assert( p->addrOpenEphm[2]>=0 );
|
|
addr = p->addrOpenEphm[2];
|
|
sqlite3VdbeChangeP2(v, addr, p->pOrderBy->nExpr+2);
|
|
pKeyInfo->nField = nOrderByExpr;
|
|
sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
|
|
pKeyInfo = 0;
|
|
generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
|
|
}
|
|
|
|
sqliteFree(pKeyInfo);
|
|
}
|
|
|
|
multi_select_end:
|
|
return rc;
|
|
}
|
|
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
|
|
|
|
#ifndef SQLITE_OMIT_VIEW
|
|
/*
|
|
** Scan through the expression pExpr. Replace every reference to
|
|
** a column in table number iTable with a copy of the iColumn-th
|
|
** entry in pEList. (But leave references to the ROWID column
|
|
** unchanged.)
|
|
**
|
|
** This routine is part of the flattening procedure. A subquery
|
|
** whose result set is defined by pEList appears as entry in the
|
|
** FROM clause of a SELECT such that the VDBE cursor assigned to that
|
|
** FORM clause entry is iTable. This routine make the necessary
|
|
** changes to pExpr so that it refers directly to the source table
|
|
** of the subquery rather the result set of the subquery.
|
|
*/
|
|
static void substExprList(ExprList*,int,ExprList*); /* Forward Decl */
|
|
static void substSelect(Select *, int, ExprList *); /* Forward Decl */
|
|
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList){
|
|
if( pExpr==0 ) return;
|
|
if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
|
|
if( pExpr->iColumn<0 ){
|
|
pExpr->op = TK_NULL;
|
|
}else{
|
|
Expr *pNew;
|
|
assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
|
|
assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
|
|
pNew = pEList->a[pExpr->iColumn].pExpr;
|
|
assert( pNew!=0 );
|
|
pExpr->op = pNew->op;
|
|
assert( pExpr->pLeft==0 );
|
|
pExpr->pLeft = sqlite3ExprDup(pNew->pLeft);
|
|
assert( pExpr->pRight==0 );
|
|
pExpr->pRight = sqlite3ExprDup(pNew->pRight);
|
|
assert( pExpr->pList==0 );
|
|
pExpr->pList = sqlite3ExprListDup(pNew->pList);
|
|
pExpr->iTable = pNew->iTable;
|
|
pExpr->pTab = pNew->pTab;
|
|
pExpr->iColumn = pNew->iColumn;
|
|
pExpr->iAgg = pNew->iAgg;
|
|
sqlite3TokenCopy(&pExpr->token, &pNew->token);
|
|
sqlite3TokenCopy(&pExpr->span, &pNew->span);
|
|
pExpr->pSelect = sqlite3SelectDup(pNew->pSelect);
|
|
pExpr->flags = pNew->flags;
|
|
}
|
|
}else{
|
|
substExpr(pExpr->pLeft, iTable, pEList);
|
|
substExpr(pExpr->pRight, iTable, pEList);
|
|
substSelect(pExpr->pSelect, iTable, pEList);
|
|
substExprList(pExpr->pList, iTable, pEList);
|
|
}
|
|
}
|
|
static void substExprList(ExprList *pList, int iTable, ExprList *pEList){
|
|
int i;
|
|
if( pList==0 ) return;
|
|
for(i=0; i<pList->nExpr; i++){
|
|
substExpr(pList->a[i].pExpr, iTable, pEList);
|
|
}
|
|
}
|
|
static void substSelect(Select *p, int iTable, ExprList *pEList){
|
|
if( !p ) return;
|
|
substExprList(p->pEList, iTable, pEList);
|
|
substExprList(p->pGroupBy, iTable, pEList);
|
|
substExprList(p->pOrderBy, iTable, pEList);
|
|
substExpr(p->pHaving, iTable, pEList);
|
|
substExpr(p->pWhere, iTable, pEList);
|
|
substSelect(p->pPrior, iTable, pEList);
|
|
}
|
|
#endif /* !defined(SQLITE_OMIT_VIEW) */
|
|
|
|
#ifndef SQLITE_OMIT_VIEW
|
|
/*
|
|
** This routine attempts to flatten subqueries in order to speed
|
|
** execution. It returns 1 if it makes changes and 0 if no flattening
|
|
** occurs.
|
|
**
|
|
** To understand the concept of flattening, consider the following
|
|
** query:
|
|
**
|
|
** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
|
|
**
|
|
** The default way of implementing this query is to execute the
|
|
** subquery first and store the results in a temporary table, then
|
|
** run the outer query on that temporary table. This requires two
|
|
** passes over the data. Furthermore, because the temporary table
|
|
** has no indices, the WHERE clause on the outer query cannot be
|
|
** optimized.
|
|
**
|
|
** This routine attempts to rewrite queries such as the above into
|
|
** a single flat select, like this:
|
|
**
|
|
** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
|
|
**
|
|
** The code generated for this simpification gives the same result
|
|
** but only has to scan the data once. And because indices might
|
|
** exist on the table t1, a complete scan of the data might be
|
|
** avoided.
|
|
**
|
|
** Flattening is only attempted if all of the following are true:
|
|
**
|
|
** (1) The subquery and the outer query do not both use aggregates.
|
|
**
|
|
** (2) The subquery is not an aggregate or the outer query is not a join.
|
|
**
|
|
** (3) The subquery is not the right operand of a left outer join, or
|
|
** the subquery is not itself a join. (Ticket #306)
|
|
**
|
|
** (4) The subquery is not DISTINCT or the outer query is not a join.
|
|
**
|
|
** (5) The subquery is not DISTINCT or the outer query does not use
|
|
** aggregates.
|
|
**
|
|
** (6) The subquery does not use aggregates or the outer query is not
|
|
** DISTINCT.
|
|
**
|
|
** (7) The subquery has a FROM clause.
|
|
**
|
|
** (8) The subquery does not use LIMIT or the outer query is not a join.
|
|
**
|
|
** (9) The subquery does not use LIMIT or the outer query does not use
|
|
** aggregates.
|
|
**
|
|
** (10) The subquery does not use aggregates or the outer query does not
|
|
** use LIMIT.
|
|
**
|
|
** (11) The subquery and the outer query do not both have ORDER BY clauses.
|
|
**
|
|
** (12) The subquery is not the right term of a LEFT OUTER JOIN or the
|
|
** subquery has no WHERE clause. (added by ticket #350)
|
|
**
|
|
** (13) The subquery and outer query do not both use LIMIT
|
|
**
|
|
** (14) The subquery does not use OFFSET
|
|
**
|
|
** (15) The outer query is not part of a compound select or the
|
|
** subquery does not have both an ORDER BY and a LIMIT clause.
|
|
** (See ticket #2339)
|
|
**
|
|
** In this routine, the "p" parameter is a pointer to the outer query.
|
|
** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
|
|
** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
|
|
**
|
|
** If flattening is not attempted, this routine is a no-op and returns 0.
|
|
** If flattening is attempted this routine returns 1.
|
|
**
|
|
** All of the expression analysis must occur on both the outer query and
|
|
** the subquery before this routine runs.
|
|
*/
|
|
static int flattenSubquery(
|
|
Select *p, /* The parent or outer SELECT statement */
|
|
int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
|
|
int isAgg, /* True if outer SELECT uses aggregate functions */
|
|
int subqueryIsAgg /* True if the subquery uses aggregate functions */
|
|
){
|
|
Select *pSub; /* The inner query or "subquery" */
|
|
SrcList *pSrc; /* The FROM clause of the outer query */
|
|
SrcList *pSubSrc; /* The FROM clause of the subquery */
|
|
ExprList *pList; /* The result set of the outer query */
|
|
int iParent; /* VDBE cursor number of the pSub result set temp table */
|
|
int i; /* Loop counter */
|
|
Expr *pWhere; /* The WHERE clause */
|
|
struct SrcList_item *pSubitem; /* The subquery */
|
|
|
|
/* Check to see if flattening is permitted. Return 0 if not.
|
|
*/
|
|
if( p==0 ) return 0;
|
|
pSrc = p->pSrc;
|
|
assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
|
|
pSubitem = &pSrc->a[iFrom];
|
|
pSub = pSubitem->pSelect;
|
|
assert( pSub!=0 );
|
|
if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
|
|
if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
|
|
pSubSrc = pSub->pSrc;
|
|
assert( pSubSrc );
|
|
/* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
|
|
** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
|
|
** because they could be computed at compile-time. But when LIMIT and OFFSET
|
|
** became arbitrary expressions, we were forced to add restrictions (13)
|
|
** and (14). */
|
|
if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
|
|
if( pSub->pOffset ) return 0; /* Restriction (14) */
|
|
if( p->pRightmost && pSub->pLimit && pSub->pOrderBy ){
|
|
return 0; /* Restriction (15) */
|
|
}
|
|
if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
|
|
if( (pSub->isDistinct || pSub->pLimit)
|
|
&& (pSrc->nSrc>1 || isAgg) ){ /* Restrictions (4)(5)(8)(9) */
|
|
return 0;
|
|
}
|
|
if( p->isDistinct && subqueryIsAgg ) return 0; /* Restriction (6) */
|
|
if( (p->disallowOrderBy || p->pOrderBy) && pSub->pOrderBy ){
|
|
return 0; /* Restriction (11) */
|
|
}
|
|
|
|
/* Restriction 3: If the subquery is a join, make sure the subquery is
|
|
** not used as the right operand of an outer join. Examples of why this
|
|
** is not allowed:
|
|
**
|
|
** t1 LEFT OUTER JOIN (t2 JOIN t3)
|
|
**
|
|
** If we flatten the above, we would get
|
|
**
|
|
** (t1 LEFT OUTER JOIN t2) JOIN t3
|
|
**
|
|
** which is not at all the same thing.
|
|
*/
|
|
if( pSubSrc->nSrc>1 && (pSubitem->jointype & JT_OUTER)!=0 ){
|
|
return 0;
|
|
}
|
|
|
|
/* Restriction 12: If the subquery is the right operand of a left outer
|
|
** join, make sure the subquery has no WHERE clause.
|
|
** An examples of why this is not allowed:
|
|
**
|
|
** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
|
|
**
|
|
** If we flatten the above, we would get
|
|
**
|
|
** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
|
|
**
|
|
** But the t2.x>0 test will always fail on a NULL row of t2, which
|
|
** effectively converts the OUTER JOIN into an INNER JOIN.
|
|
*/
|
|
if( (pSubitem->jointype & JT_OUTER)!=0 && pSub->pWhere!=0 ){
|
|
return 0;
|
|
}
|
|
|
|
/* If we reach this point, it means flattening is permitted for the
|
|
** iFrom-th entry of the FROM clause in the outer query.
|
|
*/
|
|
|
|
/* Move all of the FROM elements of the subquery into the
|
|
** the FROM clause of the outer query. Before doing this, remember
|
|
** the cursor number for the original outer query FROM element in
|
|
** iParent. The iParent cursor will never be used. Subsequent code
|
|
** will scan expressions looking for iParent references and replace
|
|
** those references with expressions that resolve to the subquery FROM
|
|
** elements we are now copying in.
|
|
*/
|
|
iParent = pSubitem->iCursor;
|
|
{
|
|
int nSubSrc = pSubSrc->nSrc;
|
|
int jointype = pSubitem->jointype;
|
|
|
|
sqlite3DeleteTable(pSubitem->pTab);
|
|
sqliteFree(pSubitem->zDatabase);
|
|
sqliteFree(pSubitem->zName);
|
|
sqliteFree(pSubitem->zAlias);
|
|
if( nSubSrc>1 ){
|
|
int extra = nSubSrc - 1;
|
|
for(i=1; i<nSubSrc; i++){
|
|
pSrc = sqlite3SrcListAppend(pSrc, 0, 0);
|
|
}
|
|
p->pSrc = pSrc;
|
|
for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
|
|
pSrc->a[i] = pSrc->a[i-extra];
|
|
}
|
|
}
|
|
for(i=0; i<nSubSrc; i++){
|
|
pSrc->a[i+iFrom] = pSubSrc->a[i];
|
|
memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
|
|
}
|
|
pSrc->a[iFrom].jointype = jointype;
|
|
}
|
|
|
|
/* Now begin substituting subquery result set expressions for
|
|
** references to the iParent in the outer query.
|
|
**
|
|
** Example:
|
|
**
|
|
** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
|
|
** \ \_____________ subquery __________/ /
|
|
** \_____________________ outer query ______________________________/
|
|
**
|
|
** We look at every expression in the outer query and every place we see
|
|
** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
|
|
*/
|
|
pList = p->pEList;
|
|
for(i=0; i<pList->nExpr; i++){
|
|
Expr *pExpr;
|
|
if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
|
|
pList->a[i].zName = sqliteStrNDup((char*)pExpr->span.z, pExpr->span.n);
|
|
}
|
|
}
|
|
substExprList(p->pEList, iParent, pSub->pEList);
|
|
if( isAgg ){
|
|
substExprList(p->pGroupBy, iParent, pSub->pEList);
|
|
substExpr(p->pHaving, iParent, pSub->pEList);
|
|
}
|
|
if( pSub->pOrderBy ){
|
|
assert( p->pOrderBy==0 );
|
|
p->pOrderBy = pSub->pOrderBy;
|
|
pSub->pOrderBy = 0;
|
|
}else if( p->pOrderBy ){
|
|
substExprList(p->pOrderBy, iParent, pSub->pEList);
|
|
}
|
|
if( pSub->pWhere ){
|
|
pWhere = sqlite3ExprDup(pSub->pWhere);
|
|
}else{
|
|
pWhere = 0;
|
|
}
|
|
if( subqueryIsAgg ){
|
|
assert( p->pHaving==0 );
|
|
p->pHaving = p->pWhere;
|
|
p->pWhere = pWhere;
|
|
substExpr(p->pHaving, iParent, pSub->pEList);
|
|
p->pHaving = sqlite3ExprAnd(p->pHaving, sqlite3ExprDup(pSub->pHaving));
|
|
assert( p->pGroupBy==0 );
|
|
p->pGroupBy = sqlite3ExprListDup(pSub->pGroupBy);
|
|
}else{
|
|
substExpr(p->pWhere, iParent, pSub->pEList);
|
|
p->pWhere = sqlite3ExprAnd(p->pWhere, pWhere);
|
|
}
|
|
|
|
/* The flattened query is distinct if either the inner or the
|
|
** outer query is distinct.
|
|
*/
|
|
p->isDistinct = p->isDistinct || pSub->isDistinct;
|
|
|
|
/*
|
|
** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
|
|
**
|
|
** One is tempted to try to add a and b to combine the limits. But this
|
|
** does not work if either limit is negative.
|
|
*/
|
|
if( pSub->pLimit ){
|
|
p->pLimit = pSub->pLimit;
|
|
pSub->pLimit = 0;
|
|
}
|
|
|
|
/* Finially, delete what is left of the subquery and return
|
|
** success.
|
|
*/
|
|
sqlite3SelectDelete(pSub);
|
|
return 1;
|
|
}
|
|
#endif /* SQLITE_OMIT_VIEW */
|
|
|
|
/*
|
|
** Analyze the SELECT statement passed in as an argument to see if it
|
|
** is a simple min() or max() query. If it is and this query can be
|
|
** satisfied using a single seek to the beginning or end of an index,
|
|
** then generate the code for this SELECT and return 1. If this is not a
|
|
** simple min() or max() query, then return 0;
|
|
**
|
|
** A simply min() or max() query looks like this:
|
|
**
|
|
** SELECT min(a) FROM table;
|
|
** SELECT max(a) FROM table;
|
|
**
|
|
** The query may have only a single table in its FROM argument. There
|
|
** can be no GROUP BY or HAVING or WHERE clauses. The result set must
|
|
** be the min() or max() of a single column of the table. The column
|
|
** in the min() or max() function must be indexed.
|
|
**
|
|
** The parameters to this routine are the same as for sqlite3Select().
|
|
** See the header comment on that routine for additional information.
|
|
*/
|
|
static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
|
|
Expr *pExpr;
|
|
int iCol;
|
|
Table *pTab;
|
|
Index *pIdx;
|
|
int base;
|
|
Vdbe *v;
|
|
int seekOp;
|
|
ExprList *pEList, *pList, eList;
|
|
struct ExprList_item eListItem;
|
|
SrcList *pSrc;
|
|
int brk;
|
|
int iDb;
|
|
|
|
/* Check to see if this query is a simple min() or max() query. Return
|
|
** zero if it is not.
|
|
*/
|
|
if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
|
|
pSrc = p->pSrc;
|
|
if( pSrc->nSrc!=1 ) return 0;
|
|
pEList = p->pEList;
|
|
if( pEList->nExpr!=1 ) return 0;
|
|
pExpr = pEList->a[0].pExpr;
|
|
if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
|
|
pList = pExpr->pList;
|
|
if( pList==0 || pList->nExpr!=1 ) return 0;
|
|
if( pExpr->token.n!=3 ) return 0;
|
|
if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
|
|
seekOp = OP_Rewind;
|
|
}else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
|
|
seekOp = OP_Last;
|
|
}else{
|
|
return 0;
|
|
}
|
|
pExpr = pList->a[0].pExpr;
|
|
if( pExpr->op!=TK_COLUMN ) return 0;
|
|
iCol = pExpr->iColumn;
|
|
pTab = pSrc->a[0].pTab;
|
|
|
|
/* This optimization cannot be used with virtual tables. */
|
|
if( IsVirtual(pTab) ) return 0;
|
|
|
|
/* If we get to here, it means the query is of the correct form.
|
|
** Check to make sure we have an index and make pIdx point to the
|
|
** appropriate index. If the min() or max() is on an INTEGER PRIMARY
|
|
** key column, no index is necessary so set pIdx to NULL. If no
|
|
** usable index is found, return 0.
|
|
*/
|
|
if( iCol<0 ){
|
|
pIdx = 0;
|
|
}else{
|
|
CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
|
|
if( pColl==0 ) return 0;
|
|
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
|
assert( pIdx->nColumn>=1 );
|
|
if( pIdx->aiColumn[0]==iCol &&
|
|
0==sqlite3StrICmp(pIdx->azColl[0], pColl->zName) ){
|
|
break;
|
|
}
|
|
}
|
|
if( pIdx==0 ) return 0;
|
|
}
|
|
|
|
/* Identify column types if we will be using the callback. This
|
|
** step is skipped if the output is going to a table or a memory cell.
|
|
** The column names have already been generated in the calling function.
|
|
*/
|
|
v = sqlite3GetVdbe(pParse);
|
|
if( v==0 ) return 0;
|
|
|
|
/* If the output is destined for a temporary table, open that table.
|
|
*/
|
|
if( eDest==SRT_EphemTab ){
|
|
sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, 1);
|
|
}
|
|
|
|
/* Generating code to find the min or the max. Basically all we have
|
|
** to do is find the first or the last entry in the chosen index. If
|
|
** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
|
|
** or last entry in the main table.
|
|
*/
|
|
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
|
|
assert( iDb>=0 || pTab->isEphem );
|
|
sqlite3CodeVerifySchema(pParse, iDb);
|
|
sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
|
|
base = pSrc->a[0].iCursor;
|
|
brk = sqlite3VdbeMakeLabel(v);
|
|
computeLimitRegisters(pParse, p, brk);
|
|
if( pSrc->a[0].pSelect==0 ){
|
|
sqlite3OpenTable(pParse, base, iDb, pTab, OP_OpenRead);
|
|
}
|
|
if( pIdx==0 ){
|
|
sqlite3VdbeAddOp(v, seekOp, base, 0);
|
|
}else{
|
|
/* Even though the cursor used to open the index here is closed
|
|
** as soon as a single value has been read from it, allocate it
|
|
** using (pParse->nTab++) to prevent the cursor id from being
|
|
** reused. This is important for statements of the form
|
|
** "INSERT INTO x SELECT max() FROM x".
|
|
*/
|
|
int iIdx;
|
|
KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
|
|
iIdx = pParse->nTab++;
|
|
assert( pIdx->pSchema==pTab->pSchema );
|
|
sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
|
|
sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
|
|
(char*)pKey, P3_KEYINFO_HANDOFF);
|
|
if( seekOp==OP_Rewind ){
|
|
sqlite3VdbeAddOp(v, OP_Null, 0, 0);
|
|
sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
|
|
seekOp = OP_MoveGt;
|
|
}
|
|
if( pIdx->aSortOrder[0]==SQLITE_SO_DESC ){
|
|
/* Ticket #2514: invert the seek operator if we are using
|
|
** a descending index. */
|
|
if( seekOp==OP_Last ){
|
|
seekOp = OP_Rewind;
|
|
}else{
|
|
assert( seekOp==OP_MoveGt );
|
|
seekOp = OP_MoveLt;
|
|
}
|
|
}
|
|
sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
|
|
sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);
|
|
sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
|
|
sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
|
|
}
|
|
eList.nExpr = 1;
|
|
memset(&eListItem, 0, sizeof(eListItem));
|
|
eList.a = &eListItem;
|
|
eList.a[0].pExpr = pExpr;
|
|
selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, brk, brk, 0);
|
|
sqlite3VdbeResolveLabel(v, brk);
|
|
sqlite3VdbeAddOp(v, OP_Close, base, 0);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
** Analyze and ORDER BY or GROUP BY clause in a SELECT statement. Return
|
|
** the number of errors seen.
|
|
**
|
|
** An ORDER BY or GROUP BY is a list of expressions. If any expression
|
|
** is an integer constant, then that expression is replaced by the
|
|
** corresponding entry in the result set.
|
|
*/
|
|
static int processOrderGroupBy(
|
|
NameContext *pNC, /* Name context of the SELECT statement. */
|
|
ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
|
|
const char *zType /* Either "ORDER" or "GROUP", as appropriate */
|
|
){
|
|
int i;
|
|
ExprList *pEList = pNC->pEList; /* The result set of the SELECT */
|
|
Parse *pParse = pNC->pParse; /* The result set of the SELECT */
|
|
assert( pEList );
|
|
|
|
if( pOrderBy==0 ) return 0;
|
|
if( pOrderBy->nExpr>SQLITE_MAX_COLUMN ){
|
|
sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType);
|
|
return 1;
|
|
}
|
|
for(i=0; i<pOrderBy->nExpr; i++){
|
|
int iCol;
|
|
Expr *pE = pOrderBy->a[i].pExpr;
|
|
if( sqlite3ExprIsInteger(pE, &iCol) ){
|
|
if( iCol>0 && iCol<=pEList->nExpr ){
|
|
CollSeq *pColl = pE->pColl;
|
|
int flags = pE->flags & EP_ExpCollate;
|
|
sqlite3ExprDelete(pE);
|
|
pE = pOrderBy->a[i].pExpr = sqlite3ExprDup(pEList->a[iCol-1].pExpr);
|
|
if( pColl && flags ){
|
|
pE->pColl = pColl;
|
|
pE->flags |= flags;
|
|
}
|
|
}else{
|
|
sqlite3ErrorMsg(pParse,
|
|
"%s BY column number %d out of range - should be "
|
|
"between 1 and %d", zType, iCol, pEList->nExpr);
|
|
return 1;
|
|
}
|
|
}
|
|
if( sqlite3ExprResolveNames(pNC, pE) ){
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** This routine resolves any names used in the result set of the
|
|
** supplied SELECT statement. If the SELECT statement being resolved
|
|
** is a sub-select, then pOuterNC is a pointer to the NameContext
|
|
** of the parent SELECT.
|
|
*/
|
|
int sqlite3SelectResolve(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The SELECT statement being coded. */
|
|
NameContext *pOuterNC /* The outer name context. May be NULL. */
|
|
){
|
|
ExprList *pEList; /* Result set. */
|
|
int i; /* For-loop variable used in multiple places */
|
|
NameContext sNC; /* Local name-context */
|
|
ExprList *pGroupBy; /* The group by clause */
|
|
|
|
/* If this routine has run before, return immediately. */
|
|
if( p->isResolved ){
|
|
assert( !pOuterNC );
|
|
return SQLITE_OK;
|
|
}
|
|
p->isResolved = 1;
|
|
|
|
/* If there have already been errors, do nothing. */
|
|
if( pParse->nErr>0 ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
|
|
/* Prepare the select statement. This call will allocate all cursors
|
|
** required to handle the tables and subqueries in the FROM clause.
|
|
*/
|
|
if( prepSelectStmt(pParse, p) ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
|
|
/* Resolve the expressions in the LIMIT and OFFSET clauses. These
|
|
** are not allowed to refer to any names, so pass an empty NameContext.
|
|
*/
|
|
memset(&sNC, 0, sizeof(sNC));
|
|
sNC.pParse = pParse;
|
|
if( sqlite3ExprResolveNames(&sNC, p->pLimit) ||
|
|
sqlite3ExprResolveNames(&sNC, p->pOffset) ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
|
|
/* Set up the local name-context to pass to ExprResolveNames() to
|
|
** resolve the expression-list.
|
|
*/
|
|
sNC.allowAgg = 1;
|
|
sNC.pSrcList = p->pSrc;
|
|
sNC.pNext = pOuterNC;
|
|
|
|
/* Resolve names in the result set. */
|
|
pEList = p->pEList;
|
|
if( !pEList ) return SQLITE_ERROR;
|
|
for(i=0; i<pEList->nExpr; i++){
|
|
Expr *pX = pEList->a[i].pExpr;
|
|
if( sqlite3ExprResolveNames(&sNC, pX) ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
}
|
|
|
|
/* If there are no aggregate functions in the result-set, and no GROUP BY
|
|
** expression, do not allow aggregates in any of the other expressions.
|
|
*/
|
|
assert( !p->isAgg );
|
|
pGroupBy = p->pGroupBy;
|
|
if( pGroupBy || sNC.hasAgg ){
|
|
p->isAgg = 1;
|
|
}else{
|
|
sNC.allowAgg = 0;
|
|
}
|
|
|
|
/* If a HAVING clause is present, then there must be a GROUP BY clause.
|
|
*/
|
|
if( p->pHaving && !pGroupBy ){
|
|
sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
|
|
return SQLITE_ERROR;
|
|
}
|
|
|
|
/* Add the expression list to the name-context before parsing the
|
|
** other expressions in the SELECT statement. This is so that
|
|
** expressions in the WHERE clause (etc.) can refer to expressions by
|
|
** aliases in the result set.
|
|
**
|
|
** Minor point: If this is the case, then the expression will be
|
|
** re-evaluated for each reference to it.
|
|
*/
|
|
sNC.pEList = p->pEList;
|
|
if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
|
|
sqlite3ExprResolveNames(&sNC, p->pHaving) ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
if( p->pPrior==0 ){
|
|
if( processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
|
|
processOrderGroupBy(&sNC, pGroupBy, "GROUP") ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
}
|
|
|
|
if( sqlite3MallocFailed() ){
|
|
return SQLITE_NOMEM;
|
|
}
|
|
|
|
/* Make sure the GROUP BY clause does not contain aggregate functions.
|
|
*/
|
|
if( pGroupBy ){
|
|
struct ExprList_item *pItem;
|
|
|
|
for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
|
|
if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
|
|
sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
|
|
"the GROUP BY clause");
|
|
return SQLITE_ERROR;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* If this is one SELECT of a compound, be sure to resolve names
|
|
** in the other SELECTs.
|
|
*/
|
|
if( p->pPrior ){
|
|
return sqlite3SelectResolve(pParse, p->pPrior, pOuterNC);
|
|
}else{
|
|
return SQLITE_OK;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Reset the aggregate accumulator.
|
|
**
|
|
** The aggregate accumulator is a set of memory cells that hold
|
|
** intermediate results while calculating an aggregate. This
|
|
** routine simply stores NULLs in all of those memory cells.
|
|
*/
|
|
static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
struct AggInfo_func *pFunc;
|
|
if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
|
|
return;
|
|
}
|
|
for(i=0; i<pAggInfo->nColumn; i++){
|
|
sqlite3VdbeAddOp(v, OP_MemNull, pAggInfo->aCol[i].iMem, 0);
|
|
}
|
|
for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
|
|
sqlite3VdbeAddOp(v, OP_MemNull, pFunc->iMem, 0);
|
|
if( pFunc->iDistinct>=0 ){
|
|
Expr *pE = pFunc->pExpr;
|
|
if( pE->pList==0 || pE->pList->nExpr!=1 ){
|
|
sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
|
|
"by an expression");
|
|
pFunc->iDistinct = -1;
|
|
}else{
|
|
KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
|
|
sqlite3VdbeOp3(v, OP_OpenEphemeral, pFunc->iDistinct, 0,
|
|
(char*)pKeyInfo, P3_KEYINFO_HANDOFF);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Invoke the OP_AggFinalize opcode for every aggregate function
|
|
** in the AggInfo structure.
|
|
*/
|
|
static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
struct AggInfo_func *pF;
|
|
for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
|
|
ExprList *pList = pF->pExpr->pList;
|
|
sqlite3VdbeOp3(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0,
|
|
(void*)pF->pFunc, P3_FUNCDEF);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Update the accumulator memory cells for an aggregate based on
|
|
** the current cursor position.
|
|
*/
|
|
static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
|
|
Vdbe *v = pParse->pVdbe;
|
|
int i;
|
|
struct AggInfo_func *pF;
|
|
struct AggInfo_col *pC;
|
|
|
|
pAggInfo->directMode = 1;
|
|
for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
|
|
int nArg;
|
|
int addrNext = 0;
|
|
ExprList *pList = pF->pExpr->pList;
|
|
if( pList ){
|
|
nArg = pList->nExpr;
|
|
sqlite3ExprCodeExprList(pParse, pList);
|
|
}else{
|
|
nArg = 0;
|
|
}
|
|
if( pF->iDistinct>=0 ){
|
|
addrNext = sqlite3VdbeMakeLabel(v);
|
|
assert( nArg==1 );
|
|
codeDistinct(v, pF->iDistinct, addrNext, 1);
|
|
}
|
|
if( pF->pFunc->needCollSeq ){
|
|
CollSeq *pColl = 0;
|
|
struct ExprList_item *pItem;
|
|
int j;
|
|
assert( pList!=0 ); /* pList!=0 if pF->pFunc->needCollSeq is true */
|
|
for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
|
|
pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
|
|
}
|
|
if( !pColl ){
|
|
pColl = pParse->db->pDfltColl;
|
|
}
|
|
sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
|
|
}
|
|
sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (void*)pF->pFunc, P3_FUNCDEF);
|
|
if( addrNext ){
|
|
sqlite3VdbeResolveLabel(v, addrNext);
|
|
}
|
|
}
|
|
for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
|
|
sqlite3ExprCode(pParse, pC->pExpr);
|
|
sqlite3VdbeAddOp(v, OP_MemStore, pC->iMem, 1);
|
|
}
|
|
pAggInfo->directMode = 0;
|
|
}
|
|
|
|
|
|
/*
|
|
** Generate code for the given SELECT statement.
|
|
**
|
|
** The results are distributed in various ways depending on the
|
|
** value of eDest and iParm.
|
|
**
|
|
** eDest Value Result
|
|
** ------------ -------------------------------------------
|
|
** SRT_Callback Invoke the callback for each row of the result.
|
|
**
|
|
** SRT_Mem Store first result in memory cell iParm
|
|
**
|
|
** SRT_Set Store results as keys of table iParm.
|
|
**
|
|
** SRT_Union Store results as a key in a temporary table iParm
|
|
**
|
|
** SRT_Except Remove results from the temporary table iParm.
|
|
**
|
|
** SRT_Table Store results in temporary table iParm
|
|
**
|
|
** The table above is incomplete. Additional eDist value have be added
|
|
** since this comment was written. See the selectInnerLoop() function for
|
|
** a complete listing of the allowed values of eDest and their meanings.
|
|
**
|
|
** This routine returns the number of errors. If any errors are
|
|
** encountered, then an appropriate error message is left in
|
|
** pParse->zErrMsg.
|
|
**
|
|
** This routine does NOT free the Select structure passed in. The
|
|
** calling function needs to do that.
|
|
**
|
|
** The pParent, parentTab, and *pParentAgg fields are filled in if this
|
|
** SELECT is a subquery. This routine may try to combine this SELECT
|
|
** with its parent to form a single flat query. In so doing, it might
|
|
** change the parent query from a non-aggregate to an aggregate query.
|
|
** For that reason, the pParentAgg flag is passed as a pointer, so it
|
|
** can be changed.
|
|
**
|
|
** Example 1: The meaning of the pParent parameter.
|
|
**
|
|
** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
|
|
** \ \_______ subquery _______/ /
|
|
** \ /
|
|
** \____________________ outer query ___________________/
|
|
**
|
|
** This routine is called for the outer query first. For that call,
|
|
** pParent will be NULL. During the processing of the outer query, this
|
|
** routine is called recursively to handle the subquery. For the recursive
|
|
** call, pParent will point to the outer query. Because the subquery is
|
|
** the second element in a three-way join, the parentTab parameter will
|
|
** be 1 (the 2nd value of a 0-indexed array.)
|
|
*/
|
|
int sqlite3Select(
|
|
Parse *pParse, /* The parser context */
|
|
Select *p, /* The SELECT statement being coded. */
|
|
int eDest, /* How to dispose of the results */
|
|
int iParm, /* A parameter used by the eDest disposal method */
|
|
Select *pParent, /* Another SELECT for which this is a sub-query */
|
|
int parentTab, /* Index in pParent->pSrc of this query */
|
|
int *pParentAgg, /* True if pParent uses aggregate functions */
|
|
char *aff /* If eDest is SRT_Union, the affinity string */
|
|
){
|
|
int i, j; /* Loop counters */
|
|
WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */
|
|
Vdbe *v; /* The virtual machine under construction */
|
|
int isAgg; /* True for select lists like "count(*)" */
|
|
ExprList *pEList; /* List of columns to extract. */
|
|
SrcList *pTabList; /* List of tables to select from */
|
|
Expr *pWhere; /* The WHERE clause. May be NULL */
|
|
ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
|
|
ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
|
|
Expr *pHaving; /* The HAVING clause. May be NULL */
|
|
int isDistinct; /* True if the DISTINCT keyword is present */
|
|
int distinct; /* Table to use for the distinct set */
|
|
int rc = 1; /* Value to return from this function */
|
|
int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
|
|
AggInfo sAggInfo; /* Information used by aggregate queries */
|
|
int iEnd; /* Address of the end of the query */
|
|
|
|
if( p==0 || sqlite3MallocFailed() || pParse->nErr ){
|
|
return 1;
|
|
}
|
|
if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
|
|
memset(&sAggInfo, 0, sizeof(sAggInfo));
|
|
|
|
#ifndef SQLITE_OMIT_COMPOUND_SELECT
|
|
/* If there is are a sequence of queries, do the earlier ones first.
|
|
*/
|
|
if( p->pPrior ){
|
|
if( p->pRightmost==0 ){
|
|
Select *pLoop;
|
|
int cnt = 0;
|
|
for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
|
|
pLoop->pRightmost = p;
|
|
}
|
|
if( SQLITE_MAX_COMPOUND_SELECT>0 && cnt>SQLITE_MAX_COMPOUND_SELECT ){
|
|
sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
|
|
return 1;
|
|
}
|
|
}
|
|
return multiSelect(pParse, p, eDest, iParm, aff);
|
|
}
|
|
#endif
|
|
|
|
pOrderBy = p->pOrderBy;
|
|
if( IgnorableOrderby(eDest) ){
|
|
p->pOrderBy = 0;
|
|
}
|
|
if( sqlite3SelectResolve(pParse, p, 0) ){
|
|
goto select_end;
|
|
}
|
|
p->pOrderBy = pOrderBy;
|
|
|
|
/* Make local copies of the parameters for this query.
|
|
*/
|
|
pTabList = p->pSrc;
|
|
pWhere = p->pWhere;
|
|
pGroupBy = p->pGroupBy;
|
|
pHaving = p->pHaving;
|
|
isAgg = p->isAgg;
|
|
isDistinct = p->isDistinct;
|
|
pEList = p->pEList;
|
|
if( pEList==0 ) goto select_end;
|
|
|
|
/*
|
|
** Do not even attempt to generate any code if we have already seen
|
|
** errors before this routine starts.
|
|
*/
|
|
if( pParse->nErr>0 ) goto select_end;
|
|
|
|
/* If writing to memory or generating a set
|
|
** only a single column may be output.
|
|
*/
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
if( checkForMultiColumnSelectError(pParse, eDest, pEList->nExpr) ){
|
|
goto select_end;
|
|
}
|
|
#endif
|
|
|
|
/* ORDER BY is ignored for some destinations.
|
|
*/
|
|
if( IgnorableOrderby(eDest) ){
|
|
pOrderBy = 0;
|
|
}
|
|
|
|
/* Begin generating code.
|
|
*/
|
|
v = sqlite3GetVdbe(pParse);
|
|
if( v==0 ) goto select_end;
|
|
|
|
/* Generate code for all sub-queries in the FROM clause
|
|
*/
|
|
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
|
|
for(i=0; i<pTabList->nSrc; i++){
|
|
const char *zSavedAuthContext = 0;
|
|
int needRestoreContext;
|
|
struct SrcList_item *pItem = &pTabList->a[i];
|
|
|
|
if( pItem->pSelect==0 || pItem->isPopulated ) continue;
|
|
if( pItem->zName!=0 ){
|
|
zSavedAuthContext = pParse->zAuthContext;
|
|
pParse->zAuthContext = pItem->zName;
|
|
needRestoreContext = 1;
|
|
}else{
|
|
needRestoreContext = 0;
|
|
}
|
|
#if SQLITE_MAX_EXPR_DEPTH>0
|
|
/* Increment Parse.nHeight by the height of the largest expression
|
|
** tree refered to by this, the parent select. The child select
|
|
** may contain expression trees of at most
|
|
** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
|
|
** more conservative than necessary, but much easier than enforcing
|
|
** an exact limit.
|
|
*/
|
|
pParse->nHeight += sqlite3SelectExprHeight(p);
|
|
#endif
|
|
sqlite3Select(pParse, pItem->pSelect, SRT_EphemTab,
|
|
pItem->iCursor, p, i, &isAgg, 0);
|
|
#if SQLITE_MAX_EXPR_DEPTH>0
|
|
pParse->nHeight -= sqlite3SelectExprHeight(p);
|
|
#endif
|
|
if( needRestoreContext ){
|
|
pParse->zAuthContext = zSavedAuthContext;
|
|
}
|
|
pTabList = p->pSrc;
|
|
pWhere = p->pWhere;
|
|
if( !IgnorableOrderby(eDest) ){
|
|
pOrderBy = p->pOrderBy;
|
|
}
|
|
pGroupBy = p->pGroupBy;
|
|
pHaving = p->pHaving;
|
|
isDistinct = p->isDistinct;
|
|
}
|
|
#endif
|
|
|
|
/* Check for the special case of a min() or max() function by itself
|
|
** in the result set.
|
|
*/
|
|
if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
|
|
rc = 0;
|
|
goto select_end;
|
|
}
|
|
|
|
/* Check to see if this is a subquery that can be "flattened" into its parent.
|
|
** If flattening is a possiblity, do so and return immediately.
|
|
*/
|
|
#ifndef SQLITE_OMIT_VIEW
|
|
if( pParent && pParentAgg &&
|
|
flattenSubquery(pParent, parentTab, *pParentAgg, isAgg) ){
|
|
if( isAgg ) *pParentAgg = 1;
|
|
goto select_end;
|
|
}
|
|
#endif
|
|
|
|
/* If there is an ORDER BY clause, then this sorting
|
|
** index might end up being unused if the data can be
|
|
** extracted in pre-sorted order. If that is the case, then the
|
|
** OP_OpenEphemeral instruction will be changed to an OP_Noop once
|
|
** we figure out that the sorting index is not needed. The addrSortIndex
|
|
** variable is used to facilitate that change.
|
|
*/
|
|
if( pOrderBy ){
|
|
KeyInfo *pKeyInfo;
|
|
if( pParse->nErr ){
|
|
goto select_end;
|
|
}
|
|
pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
|
|
pOrderBy->iECursor = pParse->nTab++;
|
|
p->addrOpenEphm[2] = addrSortIndex =
|
|
sqlite3VdbeOp3(v, OP_OpenEphemeral, pOrderBy->iECursor, pOrderBy->nExpr+2, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
|
|
}else{
|
|
addrSortIndex = -1;
|
|
}
|
|
|
|
/* If the output is destined for a temporary table, open that table.
|
|
*/
|
|
if( eDest==SRT_EphemTab ){
|
|
sqlite3VdbeAddOp(v, OP_OpenEphemeral, iParm, pEList->nExpr);
|
|
}
|
|
|
|
/* Set the limiter.
|
|
*/
|
|
iEnd = sqlite3VdbeMakeLabel(v);
|
|
computeLimitRegisters(pParse, p, iEnd);
|
|
|
|
/* Open a virtual index to use for the distinct set.
|
|
*/
|
|
if( isDistinct ){
|
|
KeyInfo *pKeyInfo;
|
|
distinct = pParse->nTab++;
|
|
pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
|
|
sqlite3VdbeOp3(v, OP_OpenEphemeral, distinct, 0,
|
|
(char*)pKeyInfo, P3_KEYINFO_HANDOFF);
|
|
}else{
|
|
distinct = -1;
|
|
}
|
|
|
|
/* Aggregate and non-aggregate queries are handled differently */
|
|
if( !isAgg && pGroupBy==0 ){
|
|
/* This case is for non-aggregate queries
|
|
** Begin the database scan
|
|
*/
|
|
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy);
|
|
if( pWInfo==0 ) goto select_end;
|
|
|
|
/* If sorting index that was created by a prior OP_OpenEphemeral
|
|
** instruction ended up not being needed, then change the OP_OpenEphemeral
|
|
** into an OP_Noop.
|
|
*/
|
|
if( addrSortIndex>=0 && pOrderBy==0 ){
|
|
sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
|
|
p->addrOpenEphm[2] = -1;
|
|
}
|
|
|
|
/* Use the standard inner loop
|
|
*/
|
|
if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
|
|
iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
|
|
goto select_end;
|
|
}
|
|
|
|
/* End the database scan loop.
|
|
*/
|
|
sqlite3WhereEnd(pWInfo);
|
|
}else{
|
|
/* This is the processing for aggregate queries */
|
|
NameContext sNC; /* Name context for processing aggregate information */
|
|
int iAMem; /* First Mem address for storing current GROUP BY */
|
|
int iBMem; /* First Mem address for previous GROUP BY */
|
|
int iUseFlag; /* Mem address holding flag indicating that at least
|
|
** one row of the input to the aggregator has been
|
|
** processed */
|
|
int iAbortFlag; /* Mem address which causes query abort if positive */
|
|
int groupBySort; /* Rows come from source in GROUP BY order */
|
|
|
|
|
|
/* The following variables hold addresses or labels for parts of the
|
|
** virtual machine program we are putting together */
|
|
int addrOutputRow; /* Start of subroutine that outputs a result row */
|
|
int addrSetAbort; /* Set the abort flag and return */
|
|
int addrInitializeLoop; /* Start of code that initializes the input loop */
|
|
int addrTopOfLoop; /* Top of the input loop */
|
|
int addrGroupByChange; /* Code that runs when any GROUP BY term changes */
|
|
int addrProcessRow; /* Code to process a single input row */
|
|
int addrEnd; /* End of all processing */
|
|
int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
|
|
int addrReset; /* Subroutine for resetting the accumulator */
|
|
|
|
addrEnd = sqlite3VdbeMakeLabel(v);
|
|
|
|
/* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
|
|
** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
|
|
** SELECT statement.
|
|
*/
|
|
memset(&sNC, 0, sizeof(sNC));
|
|
sNC.pParse = pParse;
|
|
sNC.pSrcList = pTabList;
|
|
sNC.pAggInfo = &sAggInfo;
|
|
sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
|
|
sAggInfo.pGroupBy = pGroupBy;
|
|
if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
|
|
goto select_end;
|
|
}
|
|
if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
|
|
goto select_end;
|
|
}
|
|
if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
|
|
goto select_end;
|
|
}
|
|
sAggInfo.nAccumulator = sAggInfo.nColumn;
|
|
for(i=0; i<sAggInfo.nFunc; i++){
|
|
if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
|
|
goto select_end;
|
|
}
|
|
}
|
|
if( sqlite3MallocFailed() ) goto select_end;
|
|
|
|
/* Processing for aggregates with GROUP BY is very different and
|
|
** much more complex tha aggregates without a GROUP BY.
|
|
*/
|
|
if( pGroupBy ){
|
|
KeyInfo *pKeyInfo; /* Keying information for the group by clause */
|
|
|
|
/* Create labels that we will be needing
|
|
*/
|
|
|
|
addrInitializeLoop = sqlite3VdbeMakeLabel(v);
|
|
addrGroupByChange = sqlite3VdbeMakeLabel(v);
|
|
addrProcessRow = sqlite3VdbeMakeLabel(v);
|
|
|
|
/* If there is a GROUP BY clause we might need a sorting index to
|
|
** implement it. Allocate that sorting index now. If it turns out
|
|
** that we do not need it after all, the OpenEphemeral instruction
|
|
** will be converted into a Noop.
|
|
*/
|
|
sAggInfo.sortingIdx = pParse->nTab++;
|
|
pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
|
|
addrSortingIdx =
|
|
sqlite3VdbeOp3(v, OP_OpenEphemeral, sAggInfo.sortingIdx,
|
|
sAggInfo.nSortingColumn,
|
|
(char*)pKeyInfo, P3_KEYINFO_HANDOFF);
|
|
|
|
/* Initialize memory locations used by GROUP BY aggregate processing
|
|
*/
|
|
iUseFlag = pParse->nMem++;
|
|
iAbortFlag = pParse->nMem++;
|
|
iAMem = pParse->nMem;
|
|
pParse->nMem += pGroupBy->nExpr;
|
|
iBMem = pParse->nMem;
|
|
pParse->nMem += pGroupBy->nExpr;
|
|
sqlite3VdbeAddOp(v, OP_MemInt, 0, iAbortFlag);
|
|
VdbeComment((v, "# clear abort flag"));
|
|
sqlite3VdbeAddOp(v, OP_MemInt, 0, iUseFlag);
|
|
VdbeComment((v, "# indicate accumulator empty"));
|
|
sqlite3VdbeAddOp(v, OP_Goto, 0, addrInitializeLoop);
|
|
|
|
/* Generate a subroutine that outputs a single row of the result
|
|
** set. This subroutine first looks at the iUseFlag. If iUseFlag
|
|
** is less than or equal to zero, the subroutine is a no-op. If
|
|
** the processing calls for the query to abort, this subroutine
|
|
** increments the iAbortFlag memory location before returning in
|
|
** order to signal the caller to abort.
|
|
*/
|
|
addrSetAbort = sqlite3VdbeCurrentAddr(v);
|
|
sqlite3VdbeAddOp(v, OP_MemInt, 1, iAbortFlag);
|
|
VdbeComment((v, "# set abort flag"));
|
|
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
|
|
addrOutputRow = sqlite3VdbeCurrentAddr(v);
|
|
sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
|
|
VdbeComment((v, "# Groupby result generator entry point"));
|
|
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
|
|
finalizeAggFunctions(pParse, &sAggInfo);
|
|
if( pHaving ){
|
|
sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, 1);
|
|
}
|
|
rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
|
|
distinct, eDest, iParm,
|
|
addrOutputRow+1, addrSetAbort, aff);
|
|
if( rc ){
|
|
goto select_end;
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
|
|
VdbeComment((v, "# end groupby result generator"));
|
|
|
|
/* Generate a subroutine that will reset the group-by accumulator
|
|
*/
|
|
addrReset = sqlite3VdbeCurrentAddr(v);
|
|
resetAccumulator(pParse, &sAggInfo);
|
|
sqlite3VdbeAddOp(v, OP_Return, 0, 0);
|
|
|
|
/* Begin a loop that will extract all source rows in GROUP BY order.
|
|
** This might involve two separate loops with an OP_Sort in between, or
|
|
** it might be a single loop that uses an index to extract information
|
|
** in the right order to begin with.
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, addrInitializeLoop);
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
|
|
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
|
|
if( pWInfo==0 ) goto select_end;
|
|
if( pGroupBy==0 ){
|
|
/* The optimizer is able to deliver rows in group by order so
|
|
** we do not have to sort. The OP_OpenEphemeral table will be
|
|
** cancelled later because we still need to use the pKeyInfo
|
|
*/
|
|
pGroupBy = p->pGroupBy;
|
|
groupBySort = 0;
|
|
}else{
|
|
/* Rows are coming out in undetermined order. We have to push
|
|
** each row into a sorting index, terminate the first loop,
|
|
** then loop over the sorting index in order to get the output
|
|
** in sorted order
|
|
*/
|
|
groupBySort = 1;
|
|
sqlite3ExprCodeExprList(pParse, pGroupBy);
|
|
sqlite3VdbeAddOp(v, OP_Sequence, sAggInfo.sortingIdx, 0);
|
|
j = pGroupBy->nExpr+1;
|
|
for(i=0; i<sAggInfo.nColumn; i++){
|
|
struct AggInfo_col *pCol = &sAggInfo.aCol[i];
|
|
if( pCol->iSorterColumn<j ) continue;
|
|
sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn, pCol->iTable);
|
|
j++;
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);
|
|
sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
|
|
sqlite3WhereEnd(pWInfo);
|
|
sqlite3VdbeAddOp(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
|
|
VdbeComment((v, "# GROUP BY sort"));
|
|
sAggInfo.useSortingIdx = 1;
|
|
}
|
|
|
|
/* Evaluate the current GROUP BY terms and store in b0, b1, b2...
|
|
** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
|
|
** Then compare the current GROUP BY terms against the GROUP BY terms
|
|
** from the previous row currently stored in a0, a1, a2...
|
|
*/
|
|
addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
|
|
for(j=0; j<pGroupBy->nExpr; j++){
|
|
if( groupBySort ){
|
|
sqlite3VdbeAddOp(v, OP_Column, sAggInfo.sortingIdx, j);
|
|
}else{
|
|
sAggInfo.directMode = 1;
|
|
sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
|
|
}
|
|
for(j=pGroupBy->nExpr-1; j>=0; j--){
|
|
if( j<pGroupBy->nExpr-1 ){
|
|
sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
|
|
if( j==0 ){
|
|
sqlite3VdbeAddOp(v, OP_Eq, 0x200, addrProcessRow);
|
|
}else{
|
|
sqlite3VdbeAddOp(v, OP_Ne, 0x200, addrGroupByChange);
|
|
}
|
|
sqlite3VdbeChangeP3(v, -1, (void*)pKeyInfo->aColl[j], P3_COLLSEQ);
|
|
}
|
|
|
|
/* Generate code that runs whenever the GROUP BY changes.
|
|
** Change in the GROUP BY are detected by the previous code
|
|
** block. If there were no changes, this block is skipped.
|
|
**
|
|
** This code copies current group by terms in b0,b1,b2,...
|
|
** over to a0,a1,a2. It then calls the output subroutine
|
|
** and resets the aggregate accumulator registers in preparation
|
|
** for the next GROUP BY batch.
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, addrGroupByChange);
|
|
for(j=0; j<pGroupBy->nExpr; j++){
|
|
sqlite3VdbeAddOp(v, OP_MemMove, iAMem+j, iBMem+j);
|
|
}
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
|
|
VdbeComment((v, "# output one row"));
|
|
sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
|
|
VdbeComment((v, "# check abort flag"));
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
|
|
VdbeComment((v, "# reset accumulator"));
|
|
|
|
/* Update the aggregate accumulators based on the content of
|
|
** the current row
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, addrProcessRow);
|
|
updateAccumulator(pParse, &sAggInfo);
|
|
sqlite3VdbeAddOp(v, OP_MemInt, 1, iUseFlag);
|
|
VdbeComment((v, "# indicate data in accumulator"));
|
|
|
|
/* End of the loop
|
|
*/
|
|
if( groupBySort ){
|
|
sqlite3VdbeAddOp(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
|
|
}else{
|
|
sqlite3WhereEnd(pWInfo);
|
|
sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
|
|
}
|
|
|
|
/* Output the final row of result
|
|
*/
|
|
sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
|
|
VdbeComment((v, "# output final row"));
|
|
|
|
} /* endif pGroupBy */
|
|
else {
|
|
/* This case runs if the aggregate has no GROUP BY clause. The
|
|
** processing is much simpler since there is only a single row
|
|
** of output.
|
|
*/
|
|
resetAccumulator(pParse, &sAggInfo);
|
|
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
|
|
if( pWInfo==0 ) goto select_end;
|
|
updateAccumulator(pParse, &sAggInfo);
|
|
sqlite3WhereEnd(pWInfo);
|
|
finalizeAggFunctions(pParse, &sAggInfo);
|
|
pOrderBy = 0;
|
|
if( pHaving ){
|
|
sqlite3ExprIfFalse(pParse, pHaving, addrEnd, 1);
|
|
}
|
|
selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1,
|
|
eDest, iParm, addrEnd, addrEnd, aff);
|
|
}
|
|
sqlite3VdbeResolveLabel(v, addrEnd);
|
|
|
|
} /* endif aggregate query */
|
|
|
|
/* If there is an ORDER BY clause, then we need to sort the results
|
|
** and send them to the callback one by one.
|
|
*/
|
|
if( pOrderBy ){
|
|
generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_SUBQUERY
|
|
/* If this was a subquery, we have now converted the subquery into a
|
|
** temporary table. So set the SrcList_item.isPopulated flag to prevent
|
|
** this subquery from being evaluated again and to force the use of
|
|
** the temporary table.
|
|
*/
|
|
if( pParent ){
|
|
assert( pParent->pSrc->nSrc>parentTab );
|
|
assert( pParent->pSrc->a[parentTab].pSelect==p );
|
|
pParent->pSrc->a[parentTab].isPopulated = 1;
|
|
}
|
|
#endif
|
|
|
|
/* Jump here to skip this query
|
|
*/
|
|
sqlite3VdbeResolveLabel(v, iEnd);
|
|
|
|
/* The SELECT was successfully coded. Set the return code to 0
|
|
** to indicate no errors.
|
|
*/
|
|
rc = 0;
|
|
|
|
/* Control jumps to here if an error is encountered above, or upon
|
|
** successful coding of the SELECT.
|
|
*/
|
|
select_end:
|
|
|
|
/* Identify column names if we will be using them in a callback. This
|
|
** step is skipped if the output is going to some other destination.
|
|
*/
|
|
if( rc==SQLITE_OK && eDest==SRT_Callback ){
|
|
generateColumnNames(pParse, pTabList, pEList);
|
|
}
|
|
|
|
sqliteFree(sAggInfo.aCol);
|
|
sqliteFree(sAggInfo.aFunc);
|
|
return rc;
|
|
}
|
|
|
|
#if defined(SQLITE_DEBUG)
|
|
/*
|
|
*******************************************************************************
|
|
** The following code is used for testing and debugging only. The code
|
|
** that follows does not appear in normal builds.
|
|
**
|
|
** These routines are used to print out the content of all or part of a
|
|
** parse structures such as Select or Expr. Such printouts are useful
|
|
** for helping to understand what is happening inside the code generator
|
|
** during the execution of complex SELECT statements.
|
|
**
|
|
** These routine are not called anywhere from within the normal
|
|
** code base. Then are intended to be called from within the debugger
|
|
** or from temporary "printf" statements inserted for debugging.
|
|
*/
|
|
void sqlite3PrintExpr(Expr *p){
|
|
if( p->token.z && p->token.n>0 ){
|
|
sqlite3DebugPrintf("(%.*s", p->token.n, p->token.z);
|
|
}else{
|
|
sqlite3DebugPrintf("(%d", p->op);
|
|
}
|
|
if( p->pLeft ){
|
|
sqlite3DebugPrintf(" ");
|
|
sqlite3PrintExpr(p->pLeft);
|
|
}
|
|
if( p->pRight ){
|
|
sqlite3DebugPrintf(" ");
|
|
sqlite3PrintExpr(p->pRight);
|
|
}
|
|
sqlite3DebugPrintf(")");
|
|
}
|
|
void sqlite3PrintExprList(ExprList *pList){
|
|
int i;
|
|
for(i=0; i<pList->nExpr; i++){
|
|
sqlite3PrintExpr(pList->a[i].pExpr);
|
|
if( i<pList->nExpr-1 ){
|
|
sqlite3DebugPrintf(", ");
|
|
}
|
|
}
|
|
}
|
|
void sqlite3PrintSelect(Select *p, int indent){
|
|
sqlite3DebugPrintf("%*sSELECT(%p) ", indent, "", p);
|
|
sqlite3PrintExprList(p->pEList);
|
|
sqlite3DebugPrintf("\n");
|
|
if( p->pSrc ){
|
|
char *zPrefix;
|
|
int i;
|
|
zPrefix = "FROM";
|
|
for(i=0; i<p->pSrc->nSrc; i++){
|
|
struct SrcList_item *pItem = &p->pSrc->a[i];
|
|
sqlite3DebugPrintf("%*s ", indent+6, zPrefix);
|
|
zPrefix = "";
|
|
if( pItem->pSelect ){
|
|
sqlite3DebugPrintf("(\n");
|
|
sqlite3PrintSelect(pItem->pSelect, indent+10);
|
|
sqlite3DebugPrintf("%*s)", indent+8, "");
|
|
}else if( pItem->zName ){
|
|
sqlite3DebugPrintf("%s", pItem->zName);
|
|
}
|
|
if( pItem->pTab ){
|
|
sqlite3DebugPrintf("(table: %s)", pItem->pTab->zName);
|
|
}
|
|
if( pItem->zAlias ){
|
|
sqlite3DebugPrintf(" AS %s", pItem->zAlias);
|
|
}
|
|
if( i<p->pSrc->nSrc-1 ){
|
|
sqlite3DebugPrintf(",");
|
|
}
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
}
|
|
if( p->pWhere ){
|
|
sqlite3DebugPrintf("%*s WHERE ", indent, "");
|
|
sqlite3PrintExpr(p->pWhere);
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
if( p->pGroupBy ){
|
|
sqlite3DebugPrintf("%*s GROUP BY ", indent, "");
|
|
sqlite3PrintExprList(p->pGroupBy);
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
if( p->pHaving ){
|
|
sqlite3DebugPrintf("%*s HAVING ", indent, "");
|
|
sqlite3PrintExpr(p->pHaving);
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
if( p->pOrderBy ){
|
|
sqlite3DebugPrintf("%*s ORDER BY ", indent, "");
|
|
sqlite3PrintExprList(p->pOrderBy);
|
|
sqlite3DebugPrintf("\n");
|
|
}
|
|
}
|
|
/* End of the structure debug printing code
|
|
*****************************************************************************/
|
|
#endif /* defined(SQLITE_TEST) || defined(SQLITE_DEBUG) */
|