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Experimental implementation of NULLS FIRST/LAST. This branch still has problems - the most significant of which is that ORDER BY clauses with a non-default NULLS FIRST/LAST qualifier can never use an index.

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FossilOrigin-Name: 07babb0f897fc8c9cb5b30481899c32fdd743f3f3ca508d8d957826252107dd5
This commit is contained in:
dan
2019-08-12 16:36:38 +00:00
parent 41428a97b8
commit 6e11892db8
14 changed files with 171 additions and 64 deletions
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8
src/where.c
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@@ -1031,7 +1031,7 @@ static sqlite3_index_info *allocateIndexInfo(
for(i=0; i<nOrderBy; i++){
Expr *pExpr = pOrderBy->a[i].pExpr;
pIdxOrderBy[i].iColumn = pExpr->iColumn;
pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
pIdxOrderBy[i].desc = pOrderBy->a[i].sortFlags & KEYINFO_ORDER_DESC;
}
*pmNoOmit = mNoOmit;
@@ -3836,6 +3836,7 @@ static i8 wherePathSatisfiesOrderBy(
continue;
}
}
if( pOrderBy->a[i].sortFlags & KEYINFO_ORDER_BIGNULL ) continue;
if( iColumn!=XN_ROWID ){
pColl = sqlite3ExprNNCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue;
@@ -3849,10 +3850,11 @@ static i8 wherePathSatisfiesOrderBy(
if( isMatch && (wctrlFlags & WHERE_GROUPBY)==0 ){
/* Make sure the sort order is compatible in an ORDER BY clause.
** Sort order is irrelevant for a GROUP BY clause. */
assert( (pOrderBy->a[i].sortFlags & KEYINFO_ORDER_BIGNULL)==0 );
if( revSet ){
if( (rev ^ revIdx)!=pOrderBy->a[i].sortOrder ) isMatch = 0;
if( (rev ^ revIdx)!=pOrderBy->a[i].sortFlags ) isMatch = 0;
}else{
rev = revIdx ^ pOrderBy->a[i].sortOrder;
rev = revIdx ^ pOrderBy->a[i].sortFlags;
if( rev ) *pRevMask |= MASKBIT(iLoop);
revSet = 1;
}