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Refinements to NULL processing: NULLs are indistinct for DISTINCT and UNION.

Browse Source 
Multiplying a NULL by zero yields zero. In a CASE expression, a NULL comparison
is considered false, not NULL.  With these changes, NULLs in SQLite now work
the same as in PostgreSQL and in Oracle. (CVS 600)

FossilOrigin-Name: da61aa1d238539dff9c43fd9f464d311e28d669f
This commit is contained in:
drh 2002-05-31 15:51:25 +00:00
parent 0f89253e21
commit f570f011eb
11 changed files with 279 additions and 59 deletions
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27
manifest
View File

@ -1,5 +1,5 @@
C Once\sit\sis\sopened,\sleave\sthe\scheckpoint\sjournal\sfile\sopen\sfor\sthe\nduration\sof\sa\stransaction,\srather\sthan\sclosing\sit\sand\sreopening\sit\nfor\seach\sstatement.\s\s(Ticket\s#53)\s(CVS\s599)
D 2002-05-30T12:27:03
C Refinements\sto\sNULL\sprocessing:\sNULLs\sare\sindistinct\sfor\sDISTINCT\sand\sUNION.\nMultiplying\sa\sNULL\sby\szero\syields\szero.\sIn\sa\sCASE\sexpression,\sa\sNULL\scomparison\nis\sconsidered\sfalse,\snot\sNULL.\s\sWith\sthese\schanges,\sNULLs\sin\sSQLite\snow\swork\nthe\ssame\sas\sin\sPostgreSQL\sand\sin\sOracle.\s(CVS\s600)
D 2002-05-31T15:51:25
F Makefile.in 6291a33b87d2a395aafd7646ee1ed562c6f2c28c
F Makefile.template 4e11752e0b5c7a043ca50af4296ec562857ba495
F README a4c0ba11354ef6ba0776b400d057c59da47a4cc0
@ -23,8 +23,8 @@ F src/btree.h 8abeabfe6e0b1a990b64fa457592a6482f6674f3
F src/build.c 36e42718a7a94f554ea39508993378482f5335c7
F src/delete.c a2b098cbbf518e6b641847e26de85827793bc523
F src/encode.c 346b12b46148506c32038524b95c4631ab46d760
F src/expr.c 86f0c6f26f8b573883ba3219bd91bac5d4618f6b
F src/func.c 2cd4922913234ad384ccb75dd41bc35259a8338c
F src/expr.c 6bb74762c3d86b1665b32a6a388a70eeaaca93f8
F src/func.c 061a520a122da7e4f9dcac15697bb996aac7d5df
F src/hash.c 6a6236b89c8c060c65dabd300a1c8ce7c10edb72
F src/hash.h dca065dda89d4575f3176e75e9a3dc0f4b4fb8b9
F src/insert.c 24b4e146319bada6f82a1d5eae6b38b3065d132f
@ -37,7 +37,7 @@ F src/pager.h 6fddfddd3b73aa8abc081b973886320e3c614f0e
F src/parse.y c681da701bf142967325b8791f22418e2d81552d
F src/printf.c d8032ee18b860c812eeff596c9bebfdacb7930fd
F src/random.c 19e8e00fe0df32a742f115773f57651be327cabe
F src/select.c 6e84ac2be582382a4d9a81b9594456bb46babb1c
F src/select.c 9a9f76d7d647284f41616bc120003961bea403ef
F src/shell.c 1d22fe870ee852cfb975fd000dbe3973713d0a15
F src/shell.tcl 27ecbd63dd88396ad16d81ab44f73e6c0ea9d20e
F src/sqlite.h.in 0038faa6d642de06b91143ee65a131bd831d020b
@ -51,8 +51,8 @@ F src/threadtest.c 81f0598e0f031c1bd506af337fdc1b7e8dff263f
F src/tokenize.c facec7dc0b4a13e17ad67702f548dac2f7c6a732
F src/trigger.c d02f8e3510c7c2ad948a0e8c3bb0cca8adaf80c5
F src/update.c f68375173bf5338cae3e97012708e10f206aedd9
F src/util.c a9f6e6f03e8b7137204ac15b35a58f321e38037e
F src/vdbe.c ccbee9fb9b98a2fc75400865d69531da36cbf0f1
F src/util.c 7cf46b5612f5d12601c697374b9c6b38b2332ce8
F src/vdbe.c 81ae0a1ce59d56fd4180cb8b20018c67b43d0423
F src/vdbe.h b8706429131c14b307a07aab7e47f95a9da53610
F src/where.c b054f2f23127bd57eb5f973bcd38764b875d73fe
F test/all.test e4d3821eeba751829b419cd47814bd20af4286d1
@ -63,7 +63,7 @@ F test/btree3.test 9caa9e22491dd8cd8aa36d7ac3b48b089817c895
F test/conflict.test 5149646703d3930c9111068b5cda7e2e938476e3
F test/copy.test b3cefcb520c64d7e7dfedbab06b4d4c31fa5b99a
F test/delete.test c904a62129fe102b314a96111a8417f10249e4d8
F test/expr.test 6a863adedb51b07fec745319aa6a1f939fbe0579
F test/expr.test c61a92f7d76d63d7379d58bc35245e156c9b63c3
F test/func.test 628ab513b0d9c54251a63e026a26b7b4347e54ab
F test/in.test c09312672e3f0709fa02c8e2e9cd8fb4bd6269aa
F test/index.test c8a471243bbf878974b99baf5badd59407237cf3
@ -76,10 +76,11 @@ F test/limit.test 6f98bcefc92209103bb3764c81975a6ec21d6702
F test/lock.test 3fcfd46a73119f6a18094673328a32c7b3047a8f
F test/main.test c66b564554b770ee7fdbf6a66c0cd90329bc2c85
F test/malloc.test 7ba32a9ebd3aeed52ae4aaa6d42ca37e444536fd
F test/minmax.test a234053455ffd42d785ba6edc5425374e064ff0d
F test/minmax.test 29bc5727c3e4c792d5c4745833dd4b505905819e
F test/misc1.test df281e9b26cd1db5808939c7cf2703072d555be0
F test/misuse.test a3aa2b18a97e4c409a1fcaff5151a4dd804a0162
F test/notnull.test b1f3e42fc475b0b5827b27b2e9b562081995ff30
F test/null.test 732b4ec96e1c1a10b2bc3e1008c8f1da1cc0fb30
F test/pager.test b0c0d00cd5dce0ce21f16926956b195c0ab5044c
F test/pragma.test 0b9675ef1f5ba5b43abfa337744445fc5b01a34a
F test/printf.test 3cb415073754cb8ff076f26173143c3cd293a9da
@ -89,7 +90,7 @@ F test/rowid.test 4c55943300cddf73dd0f88d40a268cab14c83274
F test/select1.test a19a8026b5c2c5bdf5384d761f3d446954b7ebf9
F test/select2.test aceea74fd895b9d007512f72499db589735bd8e4
F test/select3.test 9469c332250a75a0ef1771fb5da62dc04ec77f18
F test/select4.test 2ea8c7b7feceb853da167a39e4cce996a5c3ad88
F test/select4.test 32018b97fde7202dcb906748836fcd79410604d3
F test/select5.test c2a6c4a003316ee42cbbd689eebef8fdce0db2ac
F test/select6.test efb8d0c07a440441db87db2c4ade6904e1407e85
F test/sort.test 3b996ce7ca385f9cd559944ac0f4027a23aa546b
@ -135,7 +136,7 @@ F www/speed.tcl da8afcc1d3ccc5696cfb388a68982bc3d9f7f00f
F www/sqlite.tcl 8b5884354cb615049aed83039f8dfe1552a44279
F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
P 4debc8db929fdc201759ba211acdeadc4e30e8af
R d3c150a342080a50caa6809fc7ad7e65
P 7a24336d50e72006b2cc0e4feb292b946e79d5f3
R fa5694968411297d416326c538e47fd0
U drh
Z 7c9293e04df21e05a0d63344cf0a4066
Z 4ea8ccf14bc3e954bee7c679e23f1161

2
manifest.uuid
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@ -1 +1 @@
7a24336d50e72006b2cc0e4feb292b946e79d5f3
da61aa1d238539dff9c43fd9f464d311e28d669f

28
src/expr.c
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@ -12,7 +12,7 @@
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.65 2002/05/30 02:35:12 drh Exp $
** $Id: expr.c,v 1.66 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"
@ -933,9 +933,7 @@ void sqliteExprCode(Parse *pParse, Expr *pExpr){
}
case TK_CASE: {
int expr_end_label;
int null_result_label;
int jumpInst;
int nullBypassInst;
int addr;
int nExpr;
int i;
@ -945,44 +943,32 @@ void sqliteExprCode(Parse *pParse, Expr *pExpr){
assert(pExpr->pList->nExpr > 0);
nExpr = pExpr->pList->nExpr;
expr_end_label = sqliteVdbeMakeLabel(v);
null_result_label = sqliteVdbeMakeLabel(v);
if( pExpr->pLeft ){
sqliteExprCode(pParse, pExpr->pLeft);
nullBypassInst = sqliteVdbeAddOp(v, OP_IsNull, -1, 0);
}
for(i=0; i<nExpr; i=i+2){
sqliteExprCode(pParse, pExpr->pList->a[i].pExpr);
sqliteVdbeAddOp(v, OP_IsNull, -1, null_result_label);
if( pExpr->pLeft ){
sqliteVdbeAddOp(v, OP_Dup, 1, 1);
jumpInst = sqliteVdbeAddOp(v, OP_Ne, 0, 0);
jumpInst = sqliteVdbeAddOp(v, OP_Ne, 1, 0);
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
}else{
jumpInst = sqliteVdbeAddOp(v, OP_IfNot, 0, 0);
jumpInst = sqliteVdbeAddOp(v, OP_IfNot, 1, 0);
}
sqliteExprCode(pParse, pExpr->pList->a[i+1].pExpr);
sqliteVdbeAddOp(v, OP_Goto, 0, expr_end_label);
if( i>=nExpr-2 ){
sqliteVdbeResolveLabel(v, null_result_label);
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
if( pExpr->pRight!=0 ){
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, expr_end_label);
}
}
addr = sqliteVdbeCurrentAddr(v);
sqliteVdbeChangeP2(v, jumpInst, addr);
}
if( pExpr->pLeft ){
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
}
if( pExpr->pRight ){
sqliteExprCode(pParse, pExpr->pRight);
}else{
sqliteVdbeAddOp(v, OP_String, 0, 0);
}
sqliteVdbeResolveLabel(v, expr_end_label);
if( pExpr->pLeft ){
sqliteVdbeAddOp(v, OP_Pull, 1, 0);
sqliteVdbeAddOp(v, OP_Pop, 1, 0);
sqliteVdbeChangeP2(v, nullBypassInst, sqliteVdbeCurrentAddr(v));
}
}
break;
}

6
src/func.c
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@ -16,7 +16,7 @@
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.18 2002/05/29 23:22:23 drh Exp $
** $Id: func.c,v 1.19 2002/05/31 15:51:25 drh Exp $
*/
#include <ctype.h>
#include <math.h>
@ -362,7 +362,7 @@ static void minStep(sqlite_func *context, int argc, const char **argv){
MinMaxCtx *p;
p = sqlite_aggregate_context(context, sizeof(*p));
if( p==0 || argc<1 || argv[0]==0 ) return;
if( sqlite_aggregate_count(context)==1 || sqliteCompare(argv[0],p->z)<0 ){
if( p->z==0 || sqliteCompare(argv[0],p->z)<0 ){
int len;
if( p->z && p->z!=p->zBuf ){
sqliteFree(p->z);
@ -381,7 +381,7 @@ static void maxStep(sqlite_func *context, int argc, const char **argv){
MinMaxCtx *p;
p = sqlite_aggregate_context(context, sizeof(*p));
if( p==0 || argc<1 || argv[0]==0 ) return;
if( sqlite_aggregate_count(context)==1 || sqliteCompare(argv[0],p->z)>0 ){
if( p->z==0 || sqliteCompare(argv[0],p->z)>0 ){
int len;
if( p->z && p->z!=p->zBuf ){
sqliteFree(p->z);

13
src/select.c
View File

@ -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 1.88 2002/05/27 12:24:48 drh Exp $
** $Id: select.c,v 1.89 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"
@ -326,7 +326,12 @@ static int selectInnerLoop(
** part of the result.
*/
if( distinct>=0 && pEList && pEList->nExpr>0 ){
sqliteVdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqliteVdbeCurrentAddr(v)+7);
/* For the purposes of the DISTINCT keyword to a SELECT, NULLs
** are indistinct. This was confirmed by experiment in Oracle
** and PostgreSQL. It seems contradictory, but it appears to be
** true.
** sqliteVdbeAddOp(v, OP_IsNull, -pEList->nExpr,sqliteVdbeCurrentAddr(v)+7);
*/
sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1);
sqliteVdbeAddOp(v, OP_Distinct, distinct, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
@ -358,7 +363,7 @@ static int selectInnerLoop(
** table iParm.
*/
if( eDest==SRT_Union ){
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 1);
sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_PutStrKey, iParm, 0);
}else
@ -377,7 +382,7 @@ static int selectInnerLoop(
** the temporary table iParm.
*/
if( eDest==SRT_Except ){
int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 1);
int addr = sqliteVdbeAddOp(v, OP_MakeRecord, nColumn, 0);
sqliteVdbeAddOp(v, OP_NotFound, iParm, addr+3);
sqliteVdbeAddOp(v, OP_Delete, iParm, 0);
}else

9
src/util.c
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@ -14,7 +14,7 @@
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.44 2002/05/26 21:34:58 drh Exp $
** $Id: util.c,v 1.45 2002/05/31 15:51:25 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
@ -728,6 +728,13 @@ int sqliteSortCompare(const char *a, const char *b){
int isNumA, isNumB;
while( res==0 && *a && *b ){
if( a[1]==0 ){
res = -1;
break;
}else if( b[1]==0 ){
res = +1;
break;
}
isNumA = sqliteIsNumber(&a[1]);
isNumB = sqliteIsNumber(&b[1]);
if( isNumA ){

27
src/vdbe.c
View File

@ -30,7 +30,7 @@
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.150 2002/05/27 01:04:51 drh Exp $
** $Id: vdbe.c,v 1.151 2002/05/31 15:51:26 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@ -1769,9 +1769,28 @@ case OP_Remainder: {
int nos = tos - 1;
VERIFY( if( nos<0 ) goto not_enough_stack; )
if( ((aStack[tos].flags | aStack[nos].flags) & STK_Null)!=0 ){
int resultType = STK_Null;
if( pOp->opcode==OP_Multiply ){
/* Special case: multiplying NULL by zero gives a zero result, not a
** NULL result as it would normally. */
if( (aStack[tos].flags & (STK_Int|STK_Real))!=0
|| ((aStack[tos].flags & STK_Str)!=0 && isNumber(zStack[tos])) ){
Integerify(p,tos);
if( aStack[tos].i==0 ){
resultType = STK_Int;
aStack[nos].i = 0;
}
}else if( (aStack[nos].flags & (STK_Int|STK_Real))!=0
|| ((aStack[nos].flags & STK_Str)!=0 && isNumber(zStack[nos])) ){
Integerify(p,nos);
if( aStack[nos].i==0 ){
resultType = STK_Int;
}
}
}
POPSTACK;
Release(p, nos);
aStack[nos].flags = STK_Null;
aStack[nos].flags = resultType;
}else if( (aStack[tos].flags & aStack[nos].flags & STK_Int)==STK_Int ){
int a, b;
a = aStack[tos].i;
@ -2346,6 +2365,10 @@ case OP_NotNull: {
** created this way will not necessarily be distinct across runs.
** But they should be distinct for transient tables (created using
** OP_OpenTemp) which is what they are intended for.
**
** (Later:) The P2==1 option was intended to make NULLs distinct
** for the UNION operator. But I have since discovered that NULLs
** are indistinct for UNION. So this option is never used.
*/
case OP_MakeRecord: {
char *zNewRecord;

12
test/expr.test
View File

@ -11,7 +11,7 @@
# This file implements regression tests for SQLite library. The
# focus of this file is testing expressions.
#
# $Id: expr.test,v 1.23 2002/05/30 12:27:03 drh Exp $
# $Id: expr.test,v 1.24 2002/05/31 15:51:26 drh Exp $
set testdir [file dirname $argv0]
source $testdir/tester.tcl
@ -337,23 +337,23 @@ test_expr expr-case.1 {i1=1, i2=2} \
test_expr expr-case.2 {i1=2, i2=2} \
{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} eq
test_expr expr-case.3 {i1=NULL, i2=2} \
{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} {{}}
{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} ne
test_expr expr-case.4 {i1=2, i2=NULL} \
{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} {{}}
{CASE WHEN i1 = i2 THEN 'eq' ELSE 'ne' END} ne
test_expr expr-case.5 {i1=2} \
{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'error' END} two
test_expr expr-case.6 {i1=1} \
{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} one
test_expr expr-case.7 {i1=2} \
{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} {{}}
{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} error
test_expr expr-case.8 {i1=3} \
{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} {{}}
{CASE i1 WHEN 1 THEN 'one' WHEN NULL THEN 'two' ELSE 'error' END} error
test_expr expr-case.9 {i1=3} \
{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'error' END} error
test_expr expr-case.10 {i1=3} \
{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' END} {{}}
test_expr expr-case.11 {i1=null} \
{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 3 END} {{}}
{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 3 END} 3
test_expr expr-case.12 {i1=1} \
{CASE i1 WHEN 1 THEN null WHEN 2 THEN 'two' ELSE 3 END} {{}}
test_expr expr-case.13 {i1=7} \

16
test/minmax.test
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@ -13,7 +13,7 @@
# aggregate min() and max() functions and which are handled as
# as a special case.
#
# $Id: minmax.test,v 1.3 2002/05/29 23:22:23 drh Exp $
# $Id: minmax.test,v 1.4 2002/05/31 15:51:26 drh Exp $
set testdir [file dirname $argv0]
source $testdir/tester.tcl
@ -128,5 +128,19 @@ do_test minmax-4.1 {
(SELECT * FROM t1 UNION SELECT NULL as 'x', NULL as 'y')
}
} {1 20}
do_test minmax-4.2 {
execsql {
SELECT y, sum(x) FROM
(SELECT null, y+1 FROM t1 UNION SELECT * FROM t1)
GROUP BY y ORDER BY y;
}
} {1 1 2 5 3 22 4 92 5 90 6 0}
do_test minmax-4.3 {
execsql {
SELECT y, count(x), count(*) FROM
(SELECT null, y+1 FROM t1 UNION SELECT * FROM t1)
GROUP BY y ORDER BY y;
}
} {1 1 1 2 2 3 3 4 5 4 8 9 5 5 6 6 0 1}
finish_test

183
test/null.test Normal file
View File

@ -0,0 +1,183 @@
# 2001 September 15
#
# The author disclaims copyright to this source code. In place of
# a legal notice, here is a blessing:
#
# May you do good and not evil.
# May you find forgiveness for yourself and forgive others.
# May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for proper treatment of the special
# value NULL.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl
# Create a table and some data to work with.
#
do_test null-1.0 {
execsql {
begin;
create table t1(a,b,c);
insert into t1 values(1,0,0);
insert into t1 values(2,0,1);
insert into t1 values(3,1,0);
insert into t1 values(4,1,1);
insert into t1 values(5,null,0);
insert into t1 values(6,null,1);
insert into t1 values(7,null,null);
commit;
select * from t1;
}
} {1 0 0 2 0 1 3 1 0 4 1 1 5 {} 0 6 {} 1 7 {} {}}
# Check for how arithmetic expressions handle NULL
#
do_test null-1.1 {
execsql {
select ifnull(a+b,99) from t1;
}
} {1 2 4 5 99 99 99}
do_test null-1.2 {
execsql {
select ifnull(b*c,99) from t1;
}
} {0 0 0 1 0 99 99}
do_test null-1.2.1 {
execsql {
select ifnull(c*b,99) from t1;
}
} {0 0 0 1 0 99 99}
# Check to see how the CASE expression handles NULL values. The
# first WHEN for which the test expression is TRUE is selected.
# FALSE and UNKNOWN test expressions are skipped.
#
do_test null-2.1 {
execsql {
select ifnull(case when b<>0 then 1 else 0 end, 99) from t1;
}
} {0 0 1 1 0 0 0}
do_test null-2.2 {
execsql {
select ifnull(case when not b<>0 then 1 else 0 end, 99) from t1;
}
} {1 1 0 0 0 0 0}
do_test null-2.3 {
execsql {
select ifnull(case when b<>0 and c<>0 then 1 else 0 end, 99) from t1;
}
} {0 0 0 1 0 0 0}
do_test null-2.4 {
execsql {
select ifnull(case when not (b<>0 and c<>0) then 1 else 0 end, 99) from t1;
}
} {1 1 1 0 1 0 0}
do_test null-2.5 {
execsql {
select ifnull(case when b<>0 or c<>0 then 1 else 0 end, 99) from t1;
}
} {0 1 1 1 0 1 0}
do_test null-2.6 {
execsql {
select ifnull(case when not (b<>0 or c<>0) then 1 else 0 end, 99) from t1;
}
} {1 0 0 0 0 0 0}
do_test null-2.7 {
execsql {
select ifnull(case b when c then 1 else 0 end, 99) from t1;
}
} {1 0 0 1 0 0 0}
do_test null-2.8 {
execsql {
select ifnull(case c when b then 1 else 0 end, 99) from t1;
}
} {1 0 0 1 0 0 0}
# Check to see that NULL values are ignored in aggregate functions.
#
do_test null-3.1 {
execsql {
select count(*), count(b), count(c), sum(b), sum(c),
avg(b), avg(c), min(b), max(b) from t1;
}
} {7 4 6 2 3 0.5 0.5 0 1}
# Check to see how WHERE clauses handle NULL values. A NULL value
# is the same as UNKNOWN. The WHERE clause should only select those
# rows that are TRUE. FALSE and UNKNOWN rows are rejected.
#
do_test null-4.1 {
execsql {
select a from t1 where b<10
}
} {1 2 3 4}
do_test null-4.2 {
execsql {
select a from t1 where not b>10
}
} {1 2 3 4}
do_test null-4.3 {
execsql {
select a from t1 where b<10 or c=1;
}
} {1 2 3 4 6}
do_test null-4.4 {
execsql {
select a from t1 where b<10 and c=1;
}
} {2 4}
do_test null-4.5 {
execsql {
select a from t1 where not (b<10 and c=1);
}
} {1 3 5}
# The DISTINCT keyword on a SELECT statement should treat NULL values
# as distinct
#
do_test null-5.1 {
execsql {
select distinct b from t1 order by b;
}
} {{} 0 1}
# A UNION to two queries should treat NULL values
# as distinct
#
do_test null-6.1 {
execsql {
select b from t1 union select c from t1 order by c;
}
} {{} 0 1}
# The UNIQUE constraint only applies to non-null values
#
do_test null-7.1 {
execsql {
create table t2(a, b unique on conflict ignore);
insert into t2 values(1,1);
insert into t2 values(2,null);
insert into t2 values(3,null);
insert into t2 values(4,1);
select a from t2;
}
} {1 2 3}
do_test null-7.2 {
execsql {
create table t3(a, b, c, unique(b,c) on conflict ignore);
insert into t3 values(1,1,1);
insert into t3 values(2,null,1);
insert into t3 values(3,null,1);
insert into t3 values(4,1,1);
select a from t3;
}
} {1 2 3}
finish_test

15
test/select4.test
View File

@ -12,7 +12,7 @@
# focus of this file is testing UNION, INTERSECT and EXCEPT operators
# in SELECT statements.
#
# $Id: select4.test,v 1.8 2002/05/27 01:04:51 drh Exp $
# $Id: select4.test,v 1.9 2002/05/31 15:51:26 drh Exp $
set testdir [file dirname $argv0]
source $testdir/tester.tcl
@ -249,7 +249,8 @@ do_test select4-6.2 {
}
} {0 1 1 1 2 2 3 4 3 7 4 8 5 15}
# NULLs are distinct. Make sure the UNION operator recognizes this
# NULLs are indistinct for the UNION operator.
# Make sure the UNION operator recognizes this
#
do_test select4-6.3 {
execsql {
@ -257,8 +258,8 @@ do_test select4-6.3 {
SELECT 1 UNION SELECT 2 AS 'x'
ORDER BY x;
}
} {{} {} 1 2}
do_test select4-6.3 {
} {{} 1 2}
do_test select4-6.3.1 {
execsql {
SELECT NULL UNION ALL SELECT NULL UNION ALL
SELECT 1 UNION ALL SELECT 2 AS 'x'
@ -266,7 +267,7 @@ do_test select4-6.3 {
}
} {{} {} 1 2}
# Make sure the DISTINCT keyword treats NULLs as DISTINCT
# Make sure the DISTINCT keyword treats NULLs as indistinct.
#
do_test select4-6.4 {
execsql {
@ -281,7 +282,7 @@ do_test select4-6.5 {
SELECT NULL, 1 UNION ALL SELECT NULL, 1
);
}
} {{} 1 {} 1}
} {{} 1}
do_test select4-6.6 {
execsql {
SELECT DISTINCT * FROM (
@ -296,7 +297,7 @@ do_test select4-6.7 {
execsql {
SELECT NULL EXCEPT SELECT NULL
}
} {{}}
} {}
# Make sure column names are correct when a compound select appears as