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Fix a problem with using scalar sub-selects in window function queries.

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FossilOrigin-Name: 687fe532c274265ca77451f97829743fcb8a714d0f6b1ceb9a147ab9babdc5b5
This commit is contained in:
dan
2018-07-10 17:26:12 +00:00
parent 6ccbd2787b
commit b556f26145
4 changed files with 70 additions and 14 deletions
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39
src/window.c
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@@ -589,7 +589,9 @@ void sqlite3WindowUpdate(
typedef struct WindowRewrite WindowRewrite;
struct WindowRewrite {
Window *pWin;
SrcList *pSrc;
ExprList *pSub;
Select *pSubSelect; /* Current sub-select, if any */
};
/*
@@ -601,6 +603,24 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
struct WindowRewrite *p = pWalker->u.pRewrite;
Parse *pParse = pWalker->pParse;
/* If this function is being called from within a scalar sub-select
** that used by the SELECT statement being processed, only process
** TK_COLUMN expressions that refer to it (the outer SELECT). Do
** not process aggregates or window functions at all, as they belong
** to the scalar sub-select. */
if( p->pSubSelect ){
if( pExpr->op!=TK_COLUMN ){
return WRC_Continue;
}else{
int nSrc = p->pSrc->nSrc;
int i;
for(i=0; i<nSrc; i++){
if( pExpr->iTable==p->pSrc->a[i].iCursor ) break;
}
if( i==nSrc ) return WRC_Continue;
}
}
switch( pExpr->op ){
case TK_FUNCTION:
@@ -643,8 +663,15 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
return WRC_Continue;
}
static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){
UNUSED_PARAMETER(pWalker);
UNUSED_PARAMETER(pSelect);
struct WindowRewrite *p = pWalker->u.pRewrite;
Select *pSave = p->pSubSelect;
if( pSave==pSelect ){
return WRC_Continue;
}else{
p->pSubSelect = pSelect;
sqlite3WalkSelect(pWalker, pSelect);
p->pSubSelect = pSave;
}
return WRC_Prune;
}
@@ -655,7 +682,7 @@ static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){
** * TK_COLUMN,
** * aggregate function, or
** * window function with a Window object that is not a member of the
** linked list passed as the second argument (pWin)
** Window list passed as the second argument (pWin).
**
** Append the node to output expression-list (*ppSub). And replace it
** with a TK_COLUMN that reads the (N-1)th element of table
@@ -665,6 +692,7 @@ static int selectWindowRewriteSelectCb(Walker *pWalker, Select *pSelect){
static void selectWindowRewriteEList(
Parse *pParse,
Window *pWin,
SrcList *pSrc,
ExprList *pEList, /* Rewrite expressions in this list */
ExprList **ppSub /* IN/OUT: Sub-select expression-list */
){
@@ -676,6 +704,7 @@ static void selectWindowRewriteEList(
sRewrite.pSub = *ppSub;
sRewrite.pWin = pWin;
sRewrite.pSrc = pSrc;
sWalker.pParse = pParse;
sWalker.xExprCallback = selectWindowRewriteExprCb;
@@ -753,8 +782,8 @@ int sqlite3WindowRewrite(Parse *pParse, Select *p){
** many columns the table will have. */
pMWin->iEphCsr = pParse->nTab++;
selectWindowRewriteEList(pParse, pMWin, p->pEList, &pSublist);
selectWindowRewriteEList(pParse, pMWin, p->pOrderBy, &pSublist);
selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, &pSublist);
selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, &pSublist);
pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0);
/* Append the PARTITION BY and ORDER BY expressions to the to the