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COALESCE() and NULLIF() are now first-class expressions, not macros

that turn into CASE expressions.  They evaluate their arguments at most
once.  Patch by Kris Jurka, review and (very light) editorializing by me.
This commit is contained in:
Tom Lane
2003-02-16 02:30:39 +00:00
parent de25638d2f
commit 51972a9d5d
22 changed files with 644 additions and 107 deletions

View File

@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.243 2003/02/10 04:44:44 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.244 2003/02/16 02:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -785,7 +785,7 @@ _copyOpExpr(OpExpr *from)
}
/*
* _copyDistinctExpr
* _copyDistinctExpr (same as OpExpr)
*/
static DistinctExpr *
_copyDistinctExpr(DistinctExpr *from)
@ -919,6 +919,37 @@ _copyCaseWhen(CaseWhen *from)
return newnode;
}
/*
* _copyCoalesceExpr
*/
static CoalesceExpr *
_copyCoalesceExpr(CoalesceExpr *from)
{
CoalesceExpr *newnode = makeNode(CoalesceExpr);
COPY_SCALAR_FIELD(coalescetype);
COPY_NODE_FIELD(args);
return newnode;
}
/*
* _copyNullIfExpr (same as OpExpr)
*/
static NullIfExpr *
_copyNullIfExpr(NullIfExpr *from)
{
NullIfExpr *newnode = makeNode(NullIfExpr);
COPY_SCALAR_FIELD(opno);
COPY_SCALAR_FIELD(opfuncid);
COPY_SCALAR_FIELD(opresulttype);
COPY_SCALAR_FIELD(opretset);
COPY_NODE_FIELD(args);
return newnode;
}
/*
* _copyNullTest
*/
@ -2484,6 +2515,12 @@ copyObject(void *from)
case T_CaseWhen:
retval = _copyCaseWhen(from);
break;
case T_CoalesceExpr:
retval = _copyCoalesceExpr(from);
break;
case T_NullIfExpr:
retval = _copyNullIfExpr(from);
break;
case T_NullTest:
retval = _copyNullTest(from);
break;