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Change the way TK_SELECT_COLUMN is handled so that the subquery is only

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generated once even if part of the vector comparison is used for indexing
and the other part is now.  This change also is a pathway to vector assignment
in UPDATE statements.

FossilOrigin-Name: d8feea7dcde83179bff303072426561cfe825e58
This commit is contained in:
drh
2016-08-20 00:07:01 +00:00
parent 8d25cb90cd
commit fc7f27b9d2
7 changed files with 106 additions and 89 deletions
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35
src/wherecode.c
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@ -377,34 +377,7 @@ static int codeEqualityTerm(
assert( pLevel->pWLoop->aLTerm[iEq]==pTerm );
assert( iTarget>0 );
if( pX->op==TK_EQ || pX->op==TK_IS ){
Expr *pRight = pX->pRight;
#ifndef SQLITE_OMIT_SUBQUERY
if( pRight->op==TK_SELECT_COLUMN ){
/* This case occurs for expressions like "(a, b) == (SELECT ...)". */
WhereLoop *pLoop = pLevel->pWLoop;
int i;
Expr *pSub = pRight->pLeft;
assert( pSub->op==TK_SELECT );
for(i=pLoop->nSkip; i<iEq; i++){
Expr *pExpr = pLoop->aLTerm[i]->pExpr->pRight;
if( pExpr && pExpr->op==TK_SELECT_COLUMN && pExpr->pLeft==pSub ) break;
}
if( i==iEq ){
iReg = sqlite3CodeSubselect(pParse, pSub, 0, 0);
for(/*no-op*/; i<pLoop->nLTerm; i++){
Expr *pExpr = pLoop->aLTerm[i]->pExpr->pRight;
if( pExpr && pExpr->op==TK_SELECT_COLUMN && pExpr->pLeft==pSub ){
sqlite3VdbeAddOp2(v, OP_Copy, iReg+pExpr->iColumn, iTarget-iEq+i);
}
}
}
iReg = iTarget;
}else
#endif
{
iReg = sqlite3ExprCodeTarget(pParse, pRight, iTarget);
}
iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
}else if( pX->op==TK_ISNULL ){
iReg = iTarget;
sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
@ -1101,11 +1074,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
addrNotFound = pLevel->addrNxt;
}else{
Expr *pRight = pTerm->pExpr->pRight;
if( pRight->op==TK_SELECT_COLUMN ){
codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);
}else{
codeExprOrVector(pParse, pRight, iTarget, 1);
}
codeExprOrVector(pParse, pRight, iTarget, 1);
}
}
sqlite3VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);