bk commit into 5.0 tree (gkodinov:1.2432) BUG#26661

[kgeorge]

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ChangeSet@stripped, 2007-03-06 18:45:57+02:00, gkodinov@stripped +4 -0
  Bug #26661: The optimizer uses a special 
  "fake" st_select_lex as a current select
  when resolving ORDER BY and LIMIT for a
  UNION (sub)query. This temporary structure
  doesn't have Item_subselect descendant so
  it cannot resolve the fields in ORDER BY
  correctly.
  Fixed by making a dummy subquery class
  to resolve items in ORDER BY of the UNION and
  remove it right after so it doesn't interfere
  with the rest of the subquery code.

  mysql-test/r/subselect3.result@stripped, 2007-03-06 18:45:55+02:00, gkodinov@stripped +11
-0
    Bug #26661: test case

  mysql-test/t/subselect3.test@stripped, 2007-03-06 18:45:55+02:00, gkodinov@stripped +12 -0
    Bug #26661: test case

  sql/item_subselect.h@stripped, 2007-03-06 18:45:56+02:00, gkodinov@stripped +1 -1
    Bug #26661: dummy subquery class type

  sql/sql_union.cc@stripped, 2007-03-06 18:45:56+02:00, gkodinov@stripped +22 -0
    Bug #26661: use dummy subquery class type
    to resolve items in ORDER BY of the UNION and
    remove it right after so it doesn't interfere
    with the rest of the subquery code.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	magare.gmz
# Root:	/home/kgeorge/mysql/work/B26661-5.0-opt

--- 1.139/sql/sql_union.cc	2007-02-26 14:57:42 +02:00
+++ 1.140/sql/sql_union.cc	2007-03-06 18:45:56 +02:00
@@ -410,6 +410,19 @@
 }
 
 
+/* fake class in UNIONS to handle resolution of ORDER BY */
+class Item_fake_subselect: public Item_subselect
+{
+public:
+  subs_type substype() { return FAKE_SUBS; };
+  Item_fake_subselect () : Item_subselect() { engine= NULL; };
+  double val_real() { DBUG_ASSERT(0); return 0; };
+  longlong val_int() { DBUG_ASSERT(0); return 0; };
+  String* val_str(String*) { DBUG_ASSERT(0); return NULL; };
+  my_decimal* val_decimal(my_decimal*) { DBUG_ASSERT(0); return NULL; };
+};
+
+
 bool st_select_lex_unit::exec()
 {
   SELECT_LEX *lex_select_save= thd->lex->current_select;
@@ -550,6 +563,13 @@
 	  allocation.
 	*/
 	fake_select_lex->item_list= item_list;
+
+        /*
+          Fake st_select_lex should have item for correct resolution of 
+          fields in ORDER BY
+        */
+        if (!item)
+          item= new Item_fake_subselect();
       }
       else
       {
@@ -573,6 +593,8 @@
                             result, this, fake_select_lex);
 
       fake_select_lex->table_list.empty();
+      if (item && item->substype() == Item_subselect::FAKE_SUBS)
+        item= NULL;
       if (!saved_error)
       {
 	thd->limit_found_rows = (ulonglong)table->file->records + add_rows;

--- 1.87/sql/item_subselect.h	2007-02-21 13:05:00 +02:00
+++ 1.88/sql/item_subselect.h	2007-03-06 18:45:56 +02:00
@@ -64,7 +64,7 @@
 
   enum trans_res {RES_OK, RES_REDUCE, RES_ERROR};
   enum subs_type {UNKNOWN_SUBS, SINGLEROW_SUBS,
-		  EXISTS_SUBS, IN_SUBS, ALL_SUBS, ANY_SUBS};
+		  EXISTS_SUBS, IN_SUBS, ALL_SUBS, ANY_SUBS, FAKE_SUBS};
 
   Item_subselect();
 

--- 1.5/mysql-test/r/subselect3.result	2007-02-21 21:59:51 +02:00
+++ 1.6/mysql-test/r/subselect3.result	2007-03-06 18:45:55 +02:00
@@ -645,3 +645,14 @@
 2	2	0
 3	3	1
 drop table t1,t2;
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+SELECT a FROM 
+(SELECT * FROM t1 UNION SELECT * FROM t1 ORDER BY unknown_column) AS test;
+ERROR 42S22: Unknown column 'unknown_column' in 'order clause'
+SELECT a FROM 
+(SELECT * FROM t1 UNION SELECT * FROM t1 ORDER BY a) AS test;
+a
+1
+2
+DROP TABLE t1;

--- 1.5/mysql-test/t/subselect3.test	2007-01-27 03:10:42 +02:00
+++ 1.6/mysql-test/t/subselect3.test	2007-03-06 18:45:55 +02:00
@@ -489,3 +489,15 @@
 
 drop table t1,t2;
 
+#
+# Bug #26661: SELECT with UNION kills the daemon
+#
+CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2);
+
+--error ER_BAD_FIELD_ERROR
+SELECT a FROM 
+ (SELECT * FROM t1 UNION SELECT * FROM t1 ORDER BY unknown_column) AS test;
+SELECT a FROM 
+ (SELECT * FROM t1 UNION SELECT * FROM t1 ORDER BY a) AS test;
+
+DROP TABLE t1;