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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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26
src/expr.c
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@@ -1404,7 +1404,7 @@ ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
}
pItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
pItem->zSpan = sqlite3DbStrDup(db, pOldItem->zSpan);
pItem->sortOrder = pOldItem->sortOrder;
pItem->sortFlags = pOldItem->sortFlags;
pItem->done = 0;
pItem->bSpanIsTab = pOldItem->bSpanIsTab;
pItem->bSorterRef = pOldItem->bSorterRef;
@@ -1657,15 +1657,25 @@ vector_append_error:
/*
** Set the sort order for the last element on the given ExprList.
*/
void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder){
void sqlite3ExprListSetSortOrder(ExprList *p, int iSortOrder, int eNulls){
if( p==0 ) return;
assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC>=0 && SQLITE_SO_DESC>0 );
assert( p->nExpr>0 );
if( iSortOrder<0 ){
assert( p->a[p->nExpr-1].sortOrder==SQLITE_SO_ASC );
return;
assert( SQLITE_SO_UNDEFINED<0 && SQLITE_SO_ASC==0 && SQLITE_SO_DESC>0 );
assert( iSortOrder==SQLITE_SO_UNDEFINED
|| iSortOrder==SQLITE_SO_ASC
|| iSortOrder==SQLITE_SO_DESC
);
assert( eNulls==SQLITE_SO_UNDEFINED
|| eNulls==SQLITE_SO_ASC
|| eNulls==SQLITE_SO_DESC
);
if( iSortOrder==SQLITE_SO_UNDEFINED ) iSortOrder = SQLITE_SO_ASC;
p->a[p->nExpr-1].sortFlags = (u8)iSortOrder;
if( eNulls!=SQLITE_SO_UNDEFINED && iSortOrder!=eNulls ){
p->a[p->nExpr-1].sortFlags |= KEYINFO_ORDER_BIGNULL;
}
p->a[p->nExpr-1].sortOrder = (u8)iSortOrder;
}
/*
@@ -4909,7 +4919,7 @@ int sqlite3ExprListCompare(ExprList *pA, ExprList *pB, int iTab){
for(i=0; i<pA->nExpr; i++){
Expr *pExprA = pA->a[i].pExpr;
Expr *pExprB = pB->a[i].pExpr;
if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
if( pA->a[i].sortFlags!=pB->a[i].sortFlags ) return 1;
if( sqlite3ExprCompare(0, pExprA, pExprB, iTab) ) return 1;
}
return 0;