BUG#18405221: SHOW CREATE VIEW OUTPUT INCORRECT

Fix:
---
The issue reported is same as the BUG#14117018.
Hence backporting the patch from mysql-trunk
to mysql-5.5 and mysql-5.6

mysql-test/r/view.result

@@ -4109,3 +4109,40 @@ DROP TABLE t1;
 DROP DATABASE IF EXISTS nodb;
 CREATE VIEW nodb.a AS SELECT 1;
 ERROR 42000: Unknown database 'nodb'
+#
+# BUG#14117018 - MYSQL SERVER CREATES INVALID VIEW DEFINITION
+# BUG#18405221 - SHOW CREATE VIEW OUTPUT INCORRECT
+#
+CREATE VIEW v1 AS (SELECT '' FROM DUAL);
+CREATE VIEW v2 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+(SELECT '' FROM DUAL);
+CREATE VIEW v3 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+(SELECT '' FROM DUAL) UNION ALL
+(SELECT '' FROM DUAL);
+CREATE VIEW v4 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+(SELECT '' AS col2 FROM DUAL) UNION ALL
+(SELECT '' FROM DUAL);
+# Name for the column in select1 is set properly with or
+# without this fix.
+SHOW CREATE VIEW v1;
+View	Create View	character_set_client	collation_connection
+v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS (select '' AS `Name_exp_1`)	latin1	latin1_swedish_ci
+# Name for the column in select2 is set with this fix.
+# Without this fix, name would not have set for the
+# columns in select2.
+SHOW CREATE VIEW v2;
+View	Create View	character_set_client	collation_connection
+v2	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v2` AS (select 'BUG#14117018' AS `col1`) union all (select '' AS `Name_exp_2`)	latin1	latin1_swedish_ci
+# Name for the field item in select2 & select3 is set with this fix.
+# Without this fix, name would not have set for the
+# columns in select2 & select3.
+SHOW CREATE VIEW v3;
+View	Create View	character_set_client	collation_connection
+v3	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v3` AS (select 'BUG#14117018' AS `col1`) union all (select '' AS `Name_exp_2`) union all (select '' AS `Name_exp_3`)	latin1	latin1_swedish_ci
+# Name for the field item in select3 is set with this fix.
+# Without this fix, name would not have set for the
+# columns in select3.
+SHOW CREATE VIEW v4;
+View	Create View	character_set_client	collation_connection
+v4	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v4` AS (select 'BUG#14117018' AS `col1`) union all (select '' AS `col2`) union all (select '' AS `Name_exp_3`)	latin1	latin1_swedish_ci
+DROP VIEW v1, v2, v3, v4;

mysql-test/t/view.test

@@ -4147,6 +4147,43 @@ DROP DATABASE IF EXISTS nodb;
 --error ER_BAD_DB_ERROR
 CREATE VIEW nodb.a AS SELECT 1;
 
+
+--echo #
+--echo # BUG#14117018 - MYSQL SERVER CREATES INVALID VIEW DEFINITION
+--echo # BUG#18405221 - SHOW CREATE VIEW OUTPUT INCORRECT
+--echo #
+
+CREATE VIEW v1 AS (SELECT '' FROM DUAL);
+CREATE VIEW v2 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+                  (SELECT '' FROM DUAL);
+CREATE VIEW v3 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+                  (SELECT '' FROM DUAL) UNION ALL
+                  (SELECT '' FROM DUAL);
+CREATE VIEW v4 AS (SELECT 'BUG#14117018' AS col1 FROM DUAL) UNION ALL
+                  (SELECT '' AS col2 FROM DUAL) UNION ALL
+                  (SELECT '' FROM DUAL);
+
+--echo # Name for the column in select1 is set properly with or
+--echo # without this fix.
+SHOW CREATE VIEW v1;
+
+--echo # Name for the column in select2 is set with this fix.
+--echo # Without this fix, name would not have set for the
+--echo # columns in select2.
+SHOW CREATE VIEW v2;
+
+--echo # Name for the field item in select2 & select3 is set with this fix.
+--echo # Without this fix, name would not have set for the
+--echo # columns in select2 & select3.
+SHOW CREATE VIEW v3;
+
+--echo # Name for the field item in select3 is set with this fix.
+--echo # Without this fix, name would not have set for the
+--echo # columns in select3.
+SHOW CREATE VIEW v4;
+
+DROP VIEW v1, v2, v3, v4;
+
 # Check that all connections opened by test cases in this file are really
 # gone so execution of other tests won't be affected by their presence.
 --source include/wait_until_count_sessions.inc

sql/sql_view.cc

-/* Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2004, 2014, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -163,18 +163,23 @@ bool check_duplicate_names(List<Item> &item_list, bool gen_unique_view_name)
   Check if auto generated column names are conforming and
   possibly generate a conforming name for them if not.
 
-  @param item_list  List of Items which should be checked
+  @param lex  Lex for this thread.
+
+  @retval false Operation was a success.
+  @retval true  An error occurred.
 */
 
-static void make_valid_column_names(List<Item> &item_list)
+static bool make_valid_column_names(LEX *lex)
 {
   Item *item;
   uint name_len;
-  List_iterator_fast<Item> it(item_list);
   char buff[NAME_LEN];
+  uint column_no= 1;
   DBUG_ENTER("make_valid_column_names");
 
-  for (uint column_no= 1; (item= it++); column_no++)
+  for (SELECT_LEX *sl= &lex->select_lex; sl; sl= sl->next_select())
+  {
+    for (List_iterator_fast<Item> it(sl->item_list); (item= it++); column_no++)
     {
       if (!item->is_autogenerated_name || !check_column_name(item->name))
         continue;
@@ -183,7 +188,36 @@ static void make_valid_column_names(List<Item> &item_list)
       item->set_name(buff, name_len, system_charset_info);
     }
 
-  DBUG_VOID_RETURN;
+    /*
+      There is a possibility of generating same name for column in more than
+      one SELECT_LEX. For Example:
+
+       CREATE TABLE t1 (Name_exp_1 INT, Name_exp_2 INT, Name_exp_3 INT);
+       CREATE TABLE t2 (Name_exp_1 INT, Name_exp_2 INT, Name_exp_3 INT);
+
+       CREATE VIEW v1 AS SELECT '', t1.Name_exp_2 AS Name_exp_2 FROM t1
+                         UNION
+                         SELECT '', t2.Name_exp_1 AS Name_exp_1 from t2;
+
+      But, column names of the first SELECT_LEX is considered
+      for the output.
+
+        mysql> SELECT * FROM v1;
+        +------------+------------+
+        | Name_exp_1 | Name_exp_2 |
+        +------------+------------+
+        |            |          2 |
+        |            |          3 |
+        +------------+------------+
+
+      So, checking for duplicate names in only "sl", current
+      SELECT_LEX.
+    */
+    if (check_duplicate_names(sl->item_list, 1))
+      DBUG_RETURN(true);
+  }
+
+  DBUG_RETURN(false);
 }
 
 
@@ -590,9 +624,7 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
   }
 
   /* Check if the auto generated column names are conforming. */
-  make_valid_column_names(select_lex->item_list);
-
-  if (check_duplicate_names(select_lex->item_list, 1))
+  if (make_valid_column_names(lex))
   {
     res= TRUE;
     goto err;