From 7665e7b0a8ada42b0efa307e5feb9ba7bc0831a0 Mon Sep 17 00:00:00 2001
From: "Thomas G. Lockhart" <lockhart@fourpalms.org>
Date: Sun, 2 Aug 1998 13:34:26 +0000
Subject: [PATCH] Allows the following query to succeed: "SELECT NULL ORDER BY
 1;" There are three or four cases in transformSortClause() and I had fixed
 only one case for UNION. A second case is now fixed, in the same way; I
 assigned INT4OID to the column type for the "won't actually happen" sort.
 Didn't want to skip the code entirely, since the backend needs to _try_ a
 sort to get the NULLs right. I'm not certain under what circumstances the
 other cases are invoked and these are not yet fixed up, though perhaps they
 don't need to be...

---
 src/backend/parser/parse_clause.c | 36 ++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index a701ffca27..0e122999cb 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.21 1998/07/14 03:51:42 thomas Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_clause.c,v 1.22 1998/08/02 13:34:26 thomas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -317,6 +317,10 @@ transformSortClause(ParseState *pstate,
 {
 	List	   *s = NIL;
 
+#ifdef PARSEDEBUG
+printf("transformSortClause: entering\n");
+#endif
+
 	while (orderlist != NIL)
 	{
 		SortGroupBy *sortby = lfirst(orderlist);
@@ -326,7 +330,17 @@ transformSortClause(ParseState *pstate,
 
 		restarget = find_targetlist_entry(pstate, sortby, targetlist);
 
+#ifdef PARSEDEBUG
+printf("transformSortClause: find sorting operator for type %d\n",
+  restarget->resdom->restype);
+#endif
+
 		sortcl->resdom = resdom = restarget->resdom;
+
+		/* if we have InvalidOid, then this is a NULL field and don't need to sort */
+		if (resdom->restype == InvalidOid)
+			resdom->restype = INT4OID;
+
 		sortcl->opoid = oprid(oper(sortby->useOp,
 								   resdom->restype,
 								   resdom->restype, false));
@@ -389,6 +403,14 @@ transformSortClause(ParseState *pstate,
 					/* not a member of the sortclauses yet */
 					SortClause *sortcl = makeNode(SortClause);
 
+#ifdef PARSEDEBUG
+printf("transformSortClause: (2) find sorting operator for type %d\n",
+  tlelt->resdom->restype);
+#endif
+
+					if (tlelt->resdom->restype == InvalidOid)
+						tlelt->resdom->restype = INT4OID;
+
 					sortcl->resdom = tlelt->resdom;
 					sortcl->opoid = any_ordering_op(tlelt->resdom->restype);
 
@@ -423,6 +445,11 @@ transformSortClause(ParseState *pstate,
 				/* not a member of the sortclauses yet */
 				SortClause *sortcl = makeNode(SortClause);
 
+#ifdef PARSEDEBUG
+printf("transformSortClause: try sorting type %d\n",
+  tlelt->resdom->restype);
+#endif
+
 				sortcl->resdom = tlelt->resdom;
 				sortcl->opoid = any_ordering_op(tlelt->resdom->restype);
 
@@ -485,6 +512,13 @@ printf("transformUnionClause: types are %d -> %d\n", itype, otype);
 					{
 						((TargetEntry *)lfirst(prev_target))->resdom->restype = itype;
 					}
+#if FALSE
+					else
+					{
+						((TargetEntry *)lfirst(prev_target))->resdom->restype = UNKNOWNOID;
+						((TargetEntry *)lfirst(next_target))->resdom->restype = UNKNOWNOID;
+					}
+#endif
 				}
 				else if (itype == InvalidOid)
 				{