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Fix a problem with window frames that use "BETWEEN <start> AND 0 PRECEDING".

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FossilOrigin-Name: 7927b6b023502e990d23f30251b5b0918b547726b863bfb6747dcd7f1f71d19a
This commit is contained in:
dan
2019-03-26 16:47:17 +00:00
parent d4a591dd6b
commit 725b1cfc53
4 changed files with 66 additions and 20 deletions
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37
src/window.c
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@@ -2013,6 +2013,26 @@ Window *sqlite3WindowListDup(sqlite3 *db, Window *p){
return pRet;
}
/*
** Return true if it can be determined at compile time that expression
** pExpr evaluates to a value that, when cast to an integer, is greater
** than zero. False otherwise.
**
** If an OOM error occurs, this function sets the Parse.db.mallocFailed
** flag and returns zero.
*/
static int windowExprGtZero(Parse *pParse, Expr *pExpr){
int ret = 0;
sqlite3 *db = pParse->db;
sqlite3_value *pVal = 0;
sqlite3ValueFromExpr(db, pExpr, db->enc, SQLITE_AFF_NUMERIC, &pVal);
if( pVal && sqlite3_value_int(pVal)>0 ){
ret = 1;
}
sqlite3ValueFree(pVal);
return ret;
}
/*
** sqlite3WhereBegin() has already been called for the SELECT statement
** passed as the second argument when this function is invoked. It generates
@@ -2406,22 +2426,17 @@ void sqlite3WindowCodeStep(
** has been returned to the caller (WINDOW_RETURN_ROW), or they may
** be deleted after they enter the frame (WINDOW_AGGSTEP). */
switch( pMWin->eStart ){
case TK_FOLLOWING: {
if( pMWin->eType!=TK_RANGE ){
sqlite3 *db = pParse->db;
sqlite3_value *pVal = 0;
sqlite3ValueFromExpr(db,pMWin->pStart,db->enc,SQLITE_AFF_NUMERIC,&pVal);
if( pVal && sqlite3_value_int(pVal)>0 ){
s.eDelete = WINDOW_RETURN_ROW;
}
sqlite3ValueFree(pVal);
case TK_FOLLOWING:
if( pMWin->eType!=TK_RANGE && windowExprGtZero(pParse, pMWin->pStart) ){
s.eDelete = WINDOW_RETURN_ROW;
}
break;
}
case TK_UNBOUNDED:
if( windowCacheFrame(pMWin)==0 ){
if( pMWin->eEnd==TK_PRECEDING ){
s.eDelete = WINDOW_AGGSTEP;
if( pMWin->eType!=TK_RANGE && windowExprGtZero(pParse, pMWin->pEnd) ){
s.eDelete = WINDOW_AGGSTEP;
}
}else{
s.eDelete = WINDOW_RETURN_ROW;
}