From ec057a4380b7e4637c971ce902539723eaaf01a8 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 26 Jan 2006 17:08:19 +0000
Subject: [PATCH] Fix display of whole-row Var appearing at the top level of a
 SELECT list. While we normally prefer the notation "foo.*" for a whole-row
 Var, that does not work at SELECT top level, because in that context the
 parser will assume that what is wanted is to expand the "*" into a list of
 separate target columns, yielding behavior different from a whole-row Var. 
 We have to emit just "foo" instead in that context.  Per report from Sokolov
 Yura.

---
 src/backend/utils/adt/ruleutils.c | 81 +++++++++++++++++++++++++++------------
 1 file changed, 56 insertions(+), 25 deletions(-)

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 7c47054633..05e817ecc0 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.212 2005/12/30 18:34:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.213 2006/01/26 17:08:19 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -2018,6 +2018,7 @@ get_basic_select_query(Query *query, deparse_context *context,
 	{
 		TargetEntry *tle = (TargetEntry *) lfirst(l);
 		char	   *colname;
+		char	   *attname;
 
 		if (tle->resjunk)
 			continue;			/* ignore junk entries */
@@ -2026,7 +2027,55 @@ get_basic_select_query(Query *query, deparse_context *context,
 		sep = ", ";
 		colno++;
 
-		get_rule_expr((Node *) tle->expr, context, true);
+		/*
+		 * We special-case Var nodes rather than using get_rule_expr.
+		 * This is needed because get_rule_expr will display a whole-row Var
+		 * as "foo.*", which is the preferred notation in most contexts, but
+		 * at the top level of a SELECT list it's not right (the parser will
+		 * expand that notation into multiple columns, yielding behavior
+		 * different from a whole-row Var).  We want just "foo", instead.
+		 */
+		if (tle->expr && IsA(tle->expr, Var))
+		{
+			Var		   *var = (Var *) (tle->expr);
+			char	   *schemaname;
+			char	   *refname;
+
+			get_names_for_var(var, 0, context,
+							  &schemaname, &refname, &attname);
+			if (refname && (context->varprefix || attname == NULL))
+			{
+				if (schemaname)
+					appendStringInfo(buf, "%s.",
+									 quote_identifier(schemaname));
+
+				if (strcmp(refname, "*NEW*") == 0)
+					appendStringInfoString(buf, "new");
+				else if (strcmp(refname, "*OLD*") == 0)
+					appendStringInfoString(buf, "old");
+				else
+					appendStringInfoString(buf, quote_identifier(refname));
+
+				if (attname)
+					appendStringInfoChar(buf, '.');
+			}
+			if (attname)
+				appendStringInfoString(buf, quote_identifier(attname));
+			else
+			{
+				/*
+				 * In the whole-row Var case, refname is what the default AS
+				 * name would be.
+				 */
+				attname = refname;
+			}
+		}
+		else
+		{
+			get_rule_expr((Node *) tle->expr, context, true);
+			/* We'll show the AS name unless it's this: */
+			attname = "?column?";
+		}
 
 		/*
 		 * Figure out what the result column should be called.	In the context
@@ -2039,28 +2088,10 @@ get_basic_select_query(Query *query, deparse_context *context,
 		else
 			colname = tle->resname;
 
+		/* Show AS unless the column's name is correct as-is */
 		if (colname)			/* resname could be NULL */
 		{
-			/* Check if we must say AS ... */
-			bool		tell_as;
-
-			if (!IsA(tle->expr, Var))
-				tell_as = (strcmp(colname, "?column?") != 0);
-			else
-			{
-				Var		   *var = (Var *) (tle->expr);
-				char	   *schemaname;
-				char	   *refname;
-				char	   *attname;
-
-				get_names_for_var(var, 0, context,
-								  &schemaname, &refname, &attname);
-				tell_as = (attname == NULL ||
-						   strcmp(attname, colname) != 0);
-			}
-
-			/* and do if so */
-			if (tell_as)
+			if (attname == NULL || strcmp(attname, colname) != 0)
 				appendStringInfo(buf, " AS %s", quote_identifier(colname));
 		}
 	}
@@ -3098,9 +3129,9 @@ get_rule_expr(Node *node, deparse_context *context,
 										 quote_identifier(schemaname));
 
 					if (strcmp(refname, "*NEW*") == 0)
-						appendStringInfo(buf, "new.");
+						appendStringInfoString(buf, "new.");
 					else if (strcmp(refname, "*OLD*") == 0)
-						appendStringInfo(buf, "old.");
+						appendStringInfoString(buf, "old.");
 					else
 						appendStringInfo(buf, "%s.",
 										 quote_identifier(refname));
@@ -3108,7 +3139,7 @@ get_rule_expr(Node *node, deparse_context *context,
 				if (attname)
 					appendStringInfoString(buf, quote_identifier(attname));
 				else
-					appendStringInfo(buf, "*");
+					appendStringInfoString(buf, "*");
 			}
 			break;
 
-- 
2.11.0