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Add IS UNKNOWN, IS NOT UNKNOWN boolean tests, fix the existing boolean
tests to return the correct results per SQL9x when given NULL inputs. Reimplement these tests as well as IS [NOT] NULL to have their own expression node types, instead of depending on special functions. From Joe Conway, with a little help from Tom Lane.
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18 files changed

+662
-149
lines changed

18 files changed

+662
-149
lines changed

‎doc/src/sgml/func.sgml‎

Lines changed: 16 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.61 2001/06/15 21:03:07 tgl Exp $ -->
1+
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.62 2001/06/19 22:39:08 tgl Exp $ -->
22

33
<chapter id="functions">
44
<title>Functions and Operators</title>
@@ -273,6 +273,21 @@
273273
<productname>Microsoft Access</productname>) to work, but this may
274274
be discontinued in a future release.
275275
</para>
276+
277+
<para>
278+
Boolean values can be tested using the constructs
279+
<synopsis>
280+
<replaceable>expression</replaceable> IS TRUE
281+
<replaceable>expression</replaceable> IS NOT TRUE
282+
<replaceable>expression</replaceable> IS FALSE
283+
<replaceable>expression</replaceable> IS NOT FALSE
284+
<replaceable>expression</replaceable> IS UNKNOWN
285+
<replaceable>expression</replaceable> IS NOT UNKNOWN
286+
</synopsis>
287+
These are similar to <literal>IS NULL</literal> in that they will
288+
always return TRUE or FALSE, never NULL, even when the operand is NULL.
289+
A NULL input is treated as the logical value UNKNOWN.
290+
</para>
276291
</sect1>
277292

278293

‎doc/src/sgml/syntax.sgml‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.42 2001/05/12 22:51:35 petere Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.43 2001/06/19 22:39:08 tgl Exp $
33
-->
44

55
<chapter id="sql-syntax">
@@ -1060,7 +1060,7 @@ SELECT (5 !) - 6;
10601060
<row>
10611061
<entry><token>IS</token></entry>
10621062
<entry></entry>
1063-
<entry>test for TRUE, FALSE, NULL</entry>
1063+
<entry>test for TRUE, FALSE, UNKNOWN, NULL</entry>
10641064
</row>
10651065

10661066
<row>

‎src/backend/executor/execQual.c‎

Lines changed: 137 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.86 2001/04/19 04:29:02 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.87 2001/06/19 22:39:11 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -62,6 +62,10 @@ static Datum ExecEvalAnd(Expr *andExpr, ExprContext *econtext, bool *isNull);
6262
static Datum ExecEvalOr(Expr *orExpr, ExprContext *econtext, bool *isNull);
6363
static Datum ExecEvalCase(CaseExpr *caseExpr, ExprContext *econtext,
6464
bool *isNull, ExprDoneCond *isDone);
65+
static Datum ExecEvalNullTest(NullTest *ntest, ExprContext *econtext,
66+
bool *isNull, ExprDoneCond *isDone);
67+
static Datum ExecEvalBooleanTest(BooleanTest *btest, ExprContext *econtext,
68+
bool *isNull, ExprDoneCond *isDone);
6569

6670

6771
/*----------
@@ -1091,6 +1095,126 @@ ExecEvalCase(CaseExpr *caseExpr, ExprContext *econtext,
10911095
return (Datum) 0;
10921096
}
10931097

1098+
/* ----------------------------------------------------------------
1099+
* ExecEvalNullTest
1100+
*
1101+
* Evaluate a NullTest node.
1102+
* ----------------------------------------------------------------
1103+
*/
1104+
static Datum
1105+
ExecEvalNullTest(NullTest *ntest,
1106+
ExprContext *econtext,
1107+
bool *isNull,
1108+
ExprDoneCond *isDone)
1109+
{
1110+
Datum result;
1111+
1112+
result = ExecEvalExpr(ntest->arg, econtext, isNull, isDone);
1113+
switch (ntest->nulltesttype)
1114+
{
1115+
case IS_NULL:
1116+
if (*isNull)
1117+
{
1118+
*isNull = false;
1119+
return BoolGetDatum(true);
1120+
}
1121+
else
1122+
return BoolGetDatum(false);
1123+
case IS_NOT_NULL:
1124+
if (*isNull)
1125+
{
1126+
*isNull = false;
1127+
return BoolGetDatum(false);
1128+
}
1129+
else
1130+
return BoolGetDatum(true);
1131+
default:
1132+
elog(ERROR, "ExecEvalNullTest: unexpected nulltesttype %d",
1133+
(int) ntest->nulltesttype);
1134+
return (Datum) 0; /* keep compiler quiet */
1135+
}
1136+
}
1137+
1138+
/* ----------------------------------------------------------------
1139+
* ExecEvalBooleanTest
1140+
*
1141+
* Evaluate a BooleanTest node.
1142+
* ----------------------------------------------------------------
1143+
*/
1144+
static Datum
1145+
ExecEvalBooleanTest(BooleanTest *btest,
1146+
ExprContext *econtext,
1147+
bool *isNull,
1148+
ExprDoneCond *isDone)
1149+
{
1150+
Datum result;
1151+
1152+
result = ExecEvalExpr(btest->arg, econtext, isNull, isDone);
1153+
switch (btest->booltesttype)
1154+
{
1155+
case IS_TRUE:
1156+
if (*isNull)
1157+
{
1158+
*isNull = false;
1159+
return BoolGetDatum(false);
1160+
}
1161+
else if (DatumGetBool(result))
1162+
return BoolGetDatum(true);
1163+
else
1164+
return BoolGetDatum(false);
1165+
case IS_NOT_TRUE:
1166+
if (*isNull)
1167+
{
1168+
*isNull = false;
1169+
return BoolGetDatum(true);
1170+
}
1171+
else if (DatumGetBool(result))
1172+
return BoolGetDatum(false);
1173+
else
1174+
return BoolGetDatum(true);
1175+
case IS_FALSE:
1176+
if (*isNull)
1177+
{
1178+
*isNull = false;
1179+
return BoolGetDatum(false);
1180+
}
1181+
else if (DatumGetBool(result))
1182+
return BoolGetDatum(false);
1183+
else
1184+
return BoolGetDatum(true);
1185+
case IS_NOT_FALSE:
1186+
if (*isNull)
1187+
{
1188+
*isNull = false;
1189+
return BoolGetDatum(true);
1190+
}
1191+
else if (DatumGetBool(result))
1192+
return BoolGetDatum(true);
1193+
else
1194+
return BoolGetDatum(false);
1195+
case IS_UNKNOWN:
1196+
if (*isNull)
1197+
{
1198+
*isNull = false;
1199+
return BoolGetDatum(true);
1200+
}
1201+
else
1202+
return BoolGetDatum(false);
1203+
case IS_NOT_UNKNOWN:
1204+
if (*isNull)
1205+
{
1206+
*isNull = false;
1207+
return BoolGetDatum(false);
1208+
}
1209+
else
1210+
return BoolGetDatum(true);
1211+
default:
1212+
elog(ERROR, "ExecEvalBooleanTest: unexpected booltesttype %d",
1213+
(int) btest->booltesttype);
1214+
return (Datum) 0; /* keep compiler quiet */
1215+
}
1216+
}
1217+
10941218
/* ----------------------------------------------------------------
10951219
* ExecEvalFieldSelect
10961220
*
@@ -1266,6 +1390,18 @@ ExecEvalExpr(Node *expression,
12661390
isNull,
12671391
isDone);
12681392
break;
1393+
case T_NullTest:
1394+
retDatum = ExecEvalNullTest((NullTest *) expression,
1395+
econtext,
1396+
isNull,
1397+
isDone);
1398+
break;
1399+
case T_BooleanTest:
1400+
retDatum = ExecEvalBooleanTest((BooleanTest *) expression,
1401+
econtext,
1402+
isNull,
1403+
isDone);
1404+
break;
12691405

12701406
default:
12711407
elog(ERROR, "ExecEvalExpr: unknown expression type %d",

‎src/backend/nodes/copyfuncs.c‎

Lines changed: 43 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
* Portions Copyright (c) 1994, Regents of the University of California
1616
*
1717
* IDENTIFICATION
18-
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.144 2001/06/09 23:21:54 petere Exp $
18+
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.145 2001/06/19 22:39:11 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -1017,6 +1017,42 @@ _copyCaseWhen(CaseWhen *from)
10171017
return newnode;
10181018
}
10191019

1020+
/* ----------------
1021+
* _copyNullTest
1022+
* ----------------
1023+
*/
1024+
static NullTest *
1025+
_copyNullTest(NullTest *from)
1026+
{
1027+
NullTest *newnode = makeNode(NullTest);
1028+
1029+
/*
1030+
* copy remainder of node
1031+
*/
1032+
Node_Copy(from, newnode, arg);
1033+
newnode->nulltesttype = from->nulltesttype;
1034+
1035+
return newnode;
1036+
}
1037+
1038+
/* ----------------
1039+
* _copyBooleanTest
1040+
* ----------------
1041+
*/
1042+
static BooleanTest *
1043+
_copyBooleanTest(BooleanTest *from)
1044+
{
1045+
BooleanTest *newnode = makeNode(BooleanTest);
1046+
1047+
/*
1048+
* copy remainder of node
1049+
*/
1050+
Node_Copy(from, newnode, arg);
1051+
newnode->booltesttype = from->booltesttype;
1052+
1053+
return newnode;
1054+
}
1055+
10201056
static ArrayRef *
10211057
_copyArrayRef(ArrayRef *from)
10221058
{
@@ -2954,6 +2990,12 @@ copyObject(void *from)
29542990
case T_CaseWhen:
29552991
retval = _copyCaseWhen(from);
29562992
break;
2993+
case T_NullTest:
2994+
retval = _copyNullTest(from);
2995+
break;
2996+
case T_BooleanTest:
2997+
retval = _copyBooleanTest(from);
2998+
break;
29572999
case T_FkConstraint:
29583000
retval = _copyFkConstraint(from);
29593001
break;

‎src/backend/nodes/equalfuncs.c‎

Lines changed: 27 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,7 +20,7 @@
2020
* Portions Copyright (c) 1994, Regents of the University of California
2121
*
2222
* IDENTIFICATION
23-
* $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.92 2001/06/09 23:21:54 petere Exp $
23+
* $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.93 2001/06/19 22:39:11 tgl Exp $
2424
*
2525
*-------------------------------------------------------------------------
2626
*/
@@ -1712,6 +1712,26 @@ _equalCaseWhen(CaseWhen *a, CaseWhen *b)
17121712
return true;
17131713
}
17141714

1715+
static bool
1716+
_equalNullTest(NullTest *a, NullTest *b)
1717+
{
1718+
if (!equal(a->arg, b->arg))
1719+
return false;
1720+
if (a->nulltesttype != b->nulltesttype)
1721+
return false;
1722+
return true;
1723+
}
1724+
1725+
static bool
1726+
_equalBooleanTest(BooleanTest *a, BooleanTest *b)
1727+
{
1728+
if (!equal(a->arg, b->arg))
1729+
return false;
1730+
if (a->booltesttype != b->booltesttype)
1731+
return false;
1732+
return true;
1733+
}
1734+
17151735
/*
17161736
* Stuff from pg_list.h
17171737
*/
@@ -2120,6 +2140,12 @@ equal(void *a, void *b)
21202140
case T_CaseWhen:
21212141
retval = _equalCaseWhen(a, b);
21222142
break;
2143+
case T_NullTest:
2144+
retval = _equalNullTest(a, b);
2145+
break;
2146+
case T_BooleanTest:
2147+
retval = _equalBooleanTest(a, b);
2148+
break;
21232149
case T_FkConstraint:
21242150
retval = _equalFkConstraint(a, b);
21252151
break;

‎src/backend/nodes/outfuncs.c‎

Lines changed: 33 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,7 @@
55
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
66
* Portions Copyright (c) 1994, Regents of the University of California
77
*
8-
* $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.141 2001/05/20 20:28:18 tgl Exp $
8+
* $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.142 2001/06/19 22:39:11 tgl Exp $
99
*
1010
* NOTES
1111
* Every (plan) node in POSTGRES has an associated "out" routine which
@@ -1259,12 +1259,6 @@ _outAExpr(StringInfo str, A_Expr *node)
12591259
case NOT:
12601260
appendStringInfo(str, "NOT ");
12611261
break;
1262-
case ISNULL:
1263-
appendStringInfo(str, "ISNULL ");
1264-
break;
1265-
case NOTNULL:
1266-
appendStringInfo(str, "NOTNULL ");
1267-
break;
12681262
case OP:
12691263
_outToken(str, node->opname);
12701264
appendStringInfo(str, " ");
@@ -1402,6 +1396,32 @@ _outCaseWhen(StringInfo str, CaseWhen *node)
14021396
_outNode(str, node->result);
14031397
}
14041398

1399+
/*
1400+
* NullTest
1401+
*/
1402+
static void
1403+
_outNullTest(StringInfo str, NullTest *node)
1404+
{
1405+
appendStringInfo(str, " NULLTEST :arg ");
1406+
_outNode(str, node->arg);
1407+
1408+
appendStringInfo(str, " :nulltesttype %d ",
1409+
(int) node->nulltesttype);
1410+
}
1411+
1412+
/*
1413+
* BooleanTest
1414+
*/
1415+
static void
1416+
_outBooleanTest(StringInfo str, BooleanTest *node)
1417+
{
1418+
appendStringInfo(str, " BOOLEANTEST :arg ");
1419+
_outNode(str, node->arg);
1420+
1421+
appendStringInfo(str, " :booltesttype %d ",
1422+
(int) node->booltesttype);
1423+
}
1424+
14051425
/*
14061426
* _outNode -
14071427
* converts a Node into ascii string and append it to 'str'
@@ -1639,7 +1659,12 @@ _outNode(StringInfo str, void *obj)
16391659
case T_CaseWhen:
16401660
_outCaseWhen(str, obj);
16411661
break;
1642-
1662+
case T_NullTest:
1663+
_outNullTest(str, obj);
1664+
break;
1665+
case T_BooleanTest:
1666+
_outBooleanTest(str, obj);
1667+
break;
16431668
case T_VariableSetStmt:
16441669
break;
16451670
case T_SelectStmt:

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