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For queries of the form "SELECT p, max(q) FROM t1", the value of column p

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returned is the one on the same row that holds the maximum value of q.

FossilOrigin-Name: adb29232b659c5332b6841776372407fcc350b08
This commit is contained in:
drh
2012-02-02 17:35:43 +00:00
parent a451017d62
commit 7a95789c0c
7 changed files with 50 additions and 14 deletions
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11
src/select.c
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@@ -3596,6 +3596,8 @@ static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
Vdbe *v = pParse->pVdbe;
int i;
int regHit = 0;
int addrHitTest = 0;
struct AggInfo_func *pF;
struct AggInfo_col *pC;
@@ -3631,7 +3633,8 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
if( !pColl ){
pColl = pParse->db->pDfltColl;
}
sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, (char *)pColl, P4_COLLSEQ);
}
sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
(void*)pF->pFunc, P4_FUNCDEF);
@@ -3654,12 +3657,18 @@ static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
** Another solution would be to change the OP_SCopy used to copy cached
** values to an OP_Copy.
*/
if( regHit ){
addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit);
}
sqlite3ExprCacheClear(pParse);
for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
}
pAggInfo->directMode = 0;
sqlite3ExprCacheClear(pParse);
if( addrHitTest ){
sqlite3VdbeJumpHere(v, addrHitTest);
}
}
/*