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-rw-r--r--src/select.c71
1 files changed, 43 insertions, 28 deletions
diff --git a/src/select.c b/src/select.c
index a90877dc6..2568cf708 100644
--- a/src/select.c
+++ b/src/select.c
@@ -3160,34 +3160,43 @@ static int flattenSubquery(
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
/*
-** Analyze the SELECT statement passed as an argument to see if it
-** is a min() or max() query. Return WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX if
-** it is, or 0 otherwise. At present, a query is considered to be
-** a min()/max() query if:
+** Based on the contents of the AggInfo structure indicated by the first
+** argument, this function checks if the following are true:
**
-** 1. There is a single object in the FROM clause.
+** * the query contains just a single aggregate function,
+** * the aggregate function is either min() or max(), and
+** * the argument to the aggregate function is a column value.
**
-** 2. There is a single expression in the result set, and it is
-** either min(x) or max(x), where x is a column reference.
+** If all of the above are true, then WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX
+** is returned as appropriate. Also, *ppMinMax is set to point to the
+** list of arguments passed to the aggregate before returning.
+**
+** Or, if the conditions above are not met, *ppMinMax is set to 0 and
+** WHERE_ORDERBY_NORMAL is returned.
*/
-static u8 minMaxQuery(Select *p){
- Expr *pExpr;
- ExprList *pEList = p->pEList;
-
- if( pEList->nExpr!=1 ) return WHERE_ORDERBY_NORMAL;
- pExpr = pEList->a[0].pExpr;
- if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
- if( NEVER(ExprHasProperty(pExpr, EP_xIsSelect)) ) return 0;
- pEList = pExpr->x.pList;
- if( pEList==0 || pEList->nExpr!=1 ) return 0;
- if( pEList->a[0].pExpr->op!=TK_AGG_COLUMN ) return WHERE_ORDERBY_NORMAL;
- assert( !ExprHasProperty(pExpr, EP_IntValue) );
- if( sqlite3StrICmp(pExpr->u.zToken,"min")==0 ){
- return WHERE_ORDERBY_MIN;
- }else if( sqlite3StrICmp(pExpr->u.zToken,"max")==0 ){
- return WHERE_ORDERBY_MAX;
+static u8 minMaxQuery(AggInfo *pAggInfo, ExprList **ppMinMax){
+ int eRet = WHERE_ORDERBY_NORMAL; /* Return value */
+
+ *ppMinMax = 0;
+ if( pAggInfo->nFunc==1 ){
+ Expr *pExpr = pAggInfo->aFunc[0].pExpr; /* Aggregate function */
+ ExprList *pEList = pExpr->x.pList; /* Arguments to agg function */
+
+ assert( pExpr->op==TK_AGG_FUNCTION );
+ if( pEList && pEList->nExpr==1 && pEList->a[0].pExpr->op==TK_AGG_COLUMN ){
+ const char *zFunc = pExpr->u.zToken;
+ if( sqlite3StrICmp(zFunc, "min")==0 ){
+ eRet = WHERE_ORDERBY_MIN;
+ *ppMinMax = pEList;
+ }else if( sqlite3StrICmp(zFunc, "max")==0 ){
+ eRet = WHERE_ORDERBY_MAX;
+ *ppMinMax = pEList;
+ }
+ }
}
- return WHERE_ORDERBY_NORMAL;
+
+ assert( *ppMinMax==0 || (*ppMinMax)->nExpr==1 );
+ return eRet;
}
/*
@@ -4527,11 +4536,17 @@ int sqlite3Select(
** Refer to code and comments in where.c for details.
*/
ExprList *pMinMax = 0;
- u8 flag = minMaxQuery(p);
+ u8 flag = WHERE_ORDERBY_NORMAL;
+
+ assert( p->pGroupBy==0 );
+ assert( flag==0 );
+ if( p->pHaving==0 ){
+ flag = minMaxQuery(&sAggInfo, &pMinMax);
+ }
+ assert( flag==0 || (pMinMax!=0 && pMinMax->nExpr==1) );
+
if( flag ){
- assert( !ExprHasProperty(p->pEList->a[0].pExpr, EP_xIsSelect) );
- assert( p->pEList->a[0].pExpr->x.pList->nExpr==1 );
- pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->x.pList,0);
+ pMinMax = sqlite3ExprListDup(db, pMinMax, 0);
pDel = pMinMax;
if( pMinMax && !db->mallocFailed ){
pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0;