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NULL values are distinct. A comparison involving a NULL is always false.

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Operations on a NULL value yield a NULL result.  This change makes SQLite
operate more like the SQL spec, but it may break existing applications that
assumed the old behavior.  All the old tests pass but we still need to add
new tests to better verify the new behavior.  Fix for ticket #44. (CVS 589)

FossilOrigin-Name: 9051173742f1b0e15a809d12a0c9c98fd2c4614d
This commit is contained in:
drh
2002-05-26 20:54:33 +00:00
parent 195e6967fb
commit f5905aa7be
15 changed files with 485 additions and 238 deletions
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18
src/select.c
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@@ -12,7 +12,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.85 2002/05/25 00:18:21 drh Exp $
** $Id: select.c,v 1.86 2002/05/26 20:54:34 drh Exp $
*/
#include "sqliteInt.h"
@@ -325,13 +325,12 @@ static int selectInnerLoop(
** and this row has been seen before, then do not make this row
** part of the result.
*/
if( distinct>=0 ){
int lbl = sqliteVdbeMakeLabel(v);
if( distinct>=0 && pEList && pEList->nExpr>0 ){
sqliteVdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqliteVdbeCurrentAddr(v)+7);
sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1);
sqliteVdbeAddOp(v, OP_Distinct, distinct, lbl);
sqliteVdbeAddOp(v, OP_Distinct, distinct, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, iContinue);
sqliteVdbeResolveLabel(v, lbl);
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_PutStrKey, distinct, 0);
}
@@ -359,8 +358,8 @@ static int selectInnerLoop(
** table iParm.
*/
if( eDest==SRT_Union ){
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
sqliteVdbeAddOp(v, OP_String, iParm, 0);
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 1);
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
}else
@@ -378,7 +377,7 @@ static int selectInnerLoop(
** the temporary table iParm.
*/
if( eDest==SRT_Except ){
int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 1);
sqliteVdbeAddOp(v, OP_NotFound, iParm, addr+3);
sqliteVdbeAddOp(v, OP_Delete, iParm, 0);
}else
@@ -389,6 +388,7 @@ static int selectInnerLoop(
*/
if( eDest==SRT_Set ){
assert( nColumn==1 );
sqliteVdbeAddOp(v, OP_IsNull, -1, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
}else
@@ -1738,7 +1738,7 @@ int sqliteSelect(
startagg = sqliteVdbeAddOp(v, OP_AggNext, 0, endagg);
pParse->useAgg = 1;
if( pHaving ){
sqliteExprIfFalse(pParse, pHaving, startagg);
sqliteExprIfFalse(pParse, pHaving, startagg, 1);
}
if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,
startagg, endagg) ){