diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 00eda1b34c..14d7ed9cd1 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -6306,20 +6306,32 @@ get_rule_sortgroupclause(Index ref, List *tlist, bool force_colno,
 	 * Use column-number form if requested by caller.  Otherwise, if
 	 * expression is a constant, force it to be dumped with an explicit cast
 	 * as decoration --- this is because a simple integer constant is
-	 * ambiguous (and will be misinterpreted by findTargetlistEntry()) if we
-	 * dump it without any decoration.  If it's anything more complex than a
-	 * simple Var, then force extra parens around it, to ensure it can't be
-	 * misinterpreted as a cube() or rollup() construct.
+	 * ambiguous (and will be misinterpreted by findTargetlistEntrySQL92()) if
+	 * we dump it without any decoration.  Similarly, if it's just a Var,
+	 * there is risk of misinterpretation if the column name is reassigned in
+	 * the SELECT list, so we need to force table qualification.  And, if it's
+	 * anything more complex than a simple Var, then force extra parens around
+	 * it, to ensure it can't be misinterpreted as a cube() or rollup()
+	 * construct.
 	 */
 	if (force_colno)
 	{
 		Assert(!tle->resjunk);
 		appendStringInfo(buf, "%d", tle->resno);
 	}
-	else if (expr && IsA(expr, Const))
+	else if (!expr)
+		 /* do nothing, probably can't happen */ ;
+	else if (IsA(expr, Const))
 		get_const_expr((Const *) expr, context, 1);
-	else if (!expr || IsA(expr, Var))
+	else if (IsA(expr, Var))
+	{
+		/* Force table-qualification by setting varprefix to true */
+		bool		save_varprefix = context->varprefix;
+
+		context->varprefix = true;
 		get_rule_expr(expr, context, true);
+		context->varprefix = save_varprefix;
+	}
 	else
 	{
 		/*