From 96cfd5ab91d36ea225305cd997f661045686d5ff Mon Sep 17 00:00:00 2001
From: "igor@olga.mysql.com" <>
Date: Fri, 9 Mar 2007 01:45:32 -0800
Subject: [PATCH] Fixed bug #26661: crash when order by clause in a union
 construct references invalid name. Derived tables currently cannot use outer
 references. Thus there is no outer context for them. The 4.1 code takes this
 fact into account while the Item_field::fix_outer_field code of 5.0 lost the
 check that blocks any attempts to resolve names in outer context for derived
 tables.

---
 mysql-test/r/union.result | 11 +++++++++++
 mysql-test/t/union.test   | 13 +++++++++++++
 sql/item.cc               |  7 ++++++-
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/union.result b/mysql-test/r/union.result
index dc174e35c8f..d7e222f845e 100644
--- a/mysql-test/r/union.result
+++ b/mysql-test/r/union.result
@@ -1370,4 +1370,15 @@ select _utf8'12' union select _latin1'12345';
 12
 12
 12345
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (3),(1),(2),(4),(1);
+SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a) AS test;
+a
+1
+2
+3
+4
+SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY c) AS test;
+ERROR 42S22: Unknown column 'c' in 'order clause'
+DROP TABLE t1;
 End of 5.0 tests
diff --git a/mysql-test/t/union.test b/mysql-test/t/union.test
index bf5c5e066f0..29a9ee36481 100644
--- a/mysql-test/t/union.test
+++ b/mysql-test/t/union.test
@@ -855,4 +855,17 @@ drop table t1, t2;
 #
 select _utf8'12' union select _latin1'12345';
 
+#
+# Bug #26661: UNION with ORDER BY undefined column in FROM list
+#
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (3),(1),(2),(4),(1);
+
+SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a) AS test;
+--error 1054 
+SELECT a FROM (SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY c) AS test;
+
+DROP TABLE t1;
+
 --echo End of 5.0 tests
diff --git a/sql/item.cc b/sql/item.cc
index c5d8a62761c..80c3311b2a7 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -3441,7 +3441,12 @@ Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
   */
   Name_resolution_context *last_checked_context= context;
   Item **ref= (Item **) not_found_item;
-  Name_resolution_context *outer_context= context->outer_context;
+  SELECT_LEX *current_sel= (SELECT_LEX *) thd->lex->current_select;
+  Name_resolution_context *outer_context= 0;
+  /* Currently derived tables cannot be correlated */
+  if (current_sel->master_unit()->first_select()->linkage !=
+      DERIVED_TABLE_TYPE)
+    outer_context= context->outer_context;
   for (;
        outer_context;
        outer_context= outer_context->outer_context)