Fix for SELECT NULL.

src/backend/executor/execTuples.c

@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/executor/execTuples.c,v 1.3 1996/11/08 05:56:01 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/executor/execTuples.c,v 1.4 1996/12/07 04:37:06 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -129,6 +129,7 @@
 #include "utils/lsyscache.h"
 #include "storage/bufmgr.h"
 #include "parser/catalog_utils.h"
+#include "catalog/pg_type.h"
 
 /* ----------------------------------------------------------------
  *		  tuple table create/delete functions
@@ -938,7 +939,7 @@ ExecTypeFromTL(List *targetList)
 	    TupleDescInitEntry(typeInfo,
 			       resdom->resno,
 			       resdom->resname,
-			       get_id_typname(restype),
+			       get_id_typname(restype?restype:UNKNOWNOID),
 			       0,
 			       false);