Push down outer qualification clauses into UNION and INTERSECT subqueries.

Per pghackers discussion from back around 1-August.

src/backend/optimizer/prep/prepunion.c

@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.75 2002/08/02 18:15:06 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.76 2002/08/29 16:03:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -66,7 +66,6 @@ static List *generate_setop_tlist(List *colTypes, int flag,
 static List *generate_append_tlist(List *colTypes, bool flag,
 					 List *input_plans,
 					 List *refnames_tlist);
-static bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
 static Node *adjust_inherited_attrs_mutator(Node *node,
 							   adjust_inherited_attrs_context *context);
 
@@ -579,7 +578,7 @@ generate_append_tlist(List *colTypes, bool flag,
  * Resjunk columns are ignored if junkOK is true; otherwise presence of
  * a resjunk column will always cause a 'false' result.
  */
-static bool
+bool
 tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK)
 {
 	List	   *i;

src/include/optimizer/prep.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: prep.h,v 1.32 2002/06/20 20:29:51 momjian Exp $
+ * $Id: prep.h,v 1.33 2002/08/29 16:03:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -43,4 +43,6 @@ extern Node *adjust_inherited_attrs(Node *node,
 					   Index old_rt_index, Oid old_relid,
 					   Index new_rt_index, Oid new_relid);
 
+extern bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
+
 #endif   /* PREP_H */