From 0a2a470b08c508481da0ac60b50921b1f03a85fb Mon Sep 17 00:00:00 2001
From: Magne Mahre <magne.mahre@oracle.com>
Date: Mon, 10 Jan 2011 13:43:12 +0100
Subject: [PATCH] Bug#58970 Problem Subquery (without referencing a table)     
      and Order By

When having a UNION statement in a subquery, with no
referenced tables (or only a reference to the virtual
table 'dual'), the UNION did not allow an ORDER BY clause.

      i.e:
          SELECT(SELECT 1 AS a UNION
                 SELECT 0 AS a
                 ORDER BY a) AS b  or
          SELECT(SELECT 1 AS a FROM dual UNION
                 SELECT 0 as a
                 ORDER BY a) AS b


In addition, an ORDER BY / LIMIT clause was not accepted
in subqueries even for single SELECT statements with no
referenced tables (or with 'dual' as table reference)

   i.e:
      SELECT(SELECT 1 AS a ORDER BY a) AS b  or
      SELECT(SELECT 1 AS a FROM dual ORDER BY a) AS b

The fix was to allow an optional ORDER BY/LIMIT clause to
the grammar for these cases.

See also: Bug#57986
---
 mysql-test/r/union.result | 25 +++++++++++++++++++++++++
 mysql-test/t/union.test   | 13 +++++++++++++
 sql/sql_yacc.yy           |  3 ++-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/union.result b/mysql-test/r/union.result
index 7f0ec2275d7..1f3422c1767 100644
--- a/mysql-test/r/union.result
+++ b/mysql-test/r/union.result
@@ -1744,3 +1744,28 @@ ORDER BY c2 DESC, c1 ASC LIMIT 1
 c1	c2
 t1a	3
 DROP TABLE t1, t2;
+#
+# Bug #58970 Problem Subquery (without referencing a table) 
+#            and Order By
+#
+SELECT(SELECT 0 AS a UNION SELECT 1 AS a ORDER BY a ASC  LIMIT 1) AS dev;
+dev
+0
+SELECT(SELECT 0 AS a UNION SELECT 1 AS a ORDER BY a DESC LIMIT 1) AS dev;
+dev
+1
+SELECT(SELECT 0 AS a FROM dual UNION SELECT 1 AS a FROM dual ORDER BY a ASC  LIMIT 1) AS dev;
+dev
+0
+SELECT(SELECT 0 AS a FROM dual UNION SELECT 1 AS a FROM dual ORDER BY a DESC LIMIT 1) AS dev;
+dev
+1
+SELECT(SELECT 1 AS a ORDER BY a) AS dev;
+dev
+1
+SELECT(SELECT 1 AS a LIMIT 1) AS dev;
+dev
+1
+SELECT(SELECT 1 AS a FROM dual ORDER BY a DESC LIMIT 1) AS dev;
+dev
+1
diff --git a/mysql-test/t/union.test b/mysql-test/t/union.test
index 694f1bab15c..c6599517e90 100644
--- a/mysql-test/t/union.test
+++ b/mysql-test/t/union.test
@@ -1171,3 +1171,16 @@ SELECT c1, c2 FROM (
 ) AS res;
 
 DROP TABLE t1, t2;
+
+--echo #
+--echo # Bug #58970 Problem Subquery (without referencing a table) 
+--echo #            and Order By
+--echo #
+
+SELECT(SELECT 0 AS a UNION SELECT 1 AS a ORDER BY a ASC  LIMIT 1) AS dev;
+SELECT(SELECT 0 AS a UNION SELECT 1 AS a ORDER BY a DESC LIMIT 1) AS dev;
+SELECT(SELECT 0 AS a FROM dual UNION SELECT 1 AS a FROM dual ORDER BY a ASC  LIMIT 1) AS dev;
+SELECT(SELECT 0 AS a FROM dual UNION SELECT 1 AS a FROM dual ORDER BY a DESC LIMIT 1) AS dev;
+SELECT(SELECT 1 AS a ORDER BY a) AS dev;
+SELECT(SELECT 1 AS a LIMIT 1) AS dev;
+SELECT(SELECT 1 AS a FROM dual ORDER BY a DESC LIMIT 1) AS dev;
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index c283747156a..397afd26d8d 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -13914,7 +13914,7 @@ query_specification:
         ;
 
 query_expression_body:
-          query_specification
+          query_specification opt_union_order_or_limit
         | query_expression_body
           UNION_SYM union_option 
           {
@@ -13922,6 +13922,7 @@ query_expression_body:
               MYSQL_YYABORT;
           }
           query_specification
+          opt_union_order_or_limit
           {
             Lex->pop_context();
             $$= $1;