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authorThomas G. Lockhart <lockhart@fourpalms.org>2002-07-04 15:24:11 +0000
committerThomas G. Lockhart <lockhart@fourpalms.org>2002-07-04 15:24:11 +0000
commit68d9fbeb5511d846ce3a6f66b8955d3ca55a4b76 (patch)
tree2c916fdd1c617a90fdd143e6f68ea9c48d19f296 /src/backend/nodes/outfuncs.c
parentc7eea66c392cd3f5c914ed135d01a2e20ecb1f92 (diff)
downloadpostgresql-68d9fbeb5511d846ce3a6f66b8955d3ca55a4b76.tar.gz
postgresql-68d9fbeb5511d846ce3a6f66b8955d3ca55a4b76.zip
Implement the IS DISTINCT FROM operator per SQL99.
Reused the Expr node to hold DISTINCT which strongly resembles the existing OP info. Define DISTINCT_EXPR which strongly resembles the existing OPER_EXPR opType, but with handling for NULLs required by SQL99. We have explicit support for single-element DISTINCT comparisons all the way through to the executor. But, multi-element DISTINCTs are handled by expanding into a comparison tree in gram.y as is done for other row comparisons. Per discussions, it might be desirable to move this into one or more purpose-built nodes to be handled in the backend. Define the optional ROW keyword and token per SQL99. This allows single-element row constructs, which were formerly disallowed due to shift/reduce conflicts with parenthesized a_expr clauses. Define the SQL99 TREAT() function. Currently, use as a synonym for CAST().
Diffstat (limited to 'src/backend/nodes/outfuncs.c')
-rw-r--r--src/backend/nodes/outfuncs.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index d11cedf3e5f..2b292635186 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -5,7 +5,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.160 2002/06/20 20:29:29 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.161 2002/07/04 15:23:53 thomas Exp $
*
* NOTES
* Every (plan) node in POSTGRES has an associated "out" routine which
@@ -719,6 +719,9 @@ _outExpr(StringInfo str, Expr *node)
case OP_EXPR:
opstr = "op";
break;
+ case DISTINCT_EXPR:
+ opstr = "distinct";
+ break;
case FUNC_EXPR:
opstr = "func";
break;