Commit fc751415 authored by igor@rurik.mysql.com's avatar igor@rurik.mysql.com
Browse files

Fixed bug #18767. 

The bug caused wrong result sets for union constructs of the form
(SELECT ... ORDER BY order_list1 [LIMIT n]) ORDER BY order_list2.
For such queries order lists were concatenated and limit clause was
completely neglected.
parent bc1f4571

mysql-test/r/order_by.result

+32 −0
Original line number Diff line number Diff line
@@ -788,3 +788,35 @@ a 
2

2

DROP TABLE t1;

CREATE TABLE t1 (a int, b int);

INSERT INTO t1 VALUES (1,30), (2,20), (1,10), (2,30), (1,20), (2,10);

(SELECT b,a FROM t1 ORDER BY a,b) ORDER BY b,a;

b	a

10	1

10	2

20	1

20	2

30	1

30	2

(SELECT b FROM t1 ORDER BY b DESC) ORDER BY b ASC;

b

10

10

20

20

30

30

(SELECT b,a FROM t1 ORDER BY b,a) ORDER BY a,b;

b	a

10	1

20	1

30	1

10	2

20	2

30	2

(SELECT b,a FROM t1 ORDER by b,a LIMIT 3) ORDER by a,b;

b	a

10	1

20	1

10	2

DROP TABLE t1;

mysql-test/t/order_by.test

+14 −0
Original line number Diff line number Diff line
@@ -545,4 +545,18 @@ SELECT a FROM t1 ORDER BY a; 
(SELECT a FROM t1) ORDER BY a;

DROP TABLE t1;



#

# Bug #18767: global ORDER BY applied to a SELECT with ORDER BY either was

#             ignored or 'concatened' to the latter. 



CREATE TABLE t1 (a int, b int);

INSERT INTO t1 VALUES (1,30), (2,20), (1,10), (2,30), (1,20), (2,10);



(SELECT b,a FROM t1 ORDER BY a,b) ORDER BY b,a;

(SELECT b FROM t1 ORDER BY b DESC) ORDER BY b ASC;

(SELECT b,a FROM t1 ORDER BY b,a) ORDER BY a,b;

(SELECT b,a FROM t1 ORDER by b,a LIMIT 3) ORDER by a,b;



DROP TABLE t1;



# End of 4.1 tests

sql/sql_lex.h

+1 −0
Original line number Diff line number Diff line
@@ -400,6 +400,7 @@ class st_select_lex_unit: public st_select_lex_node { 
  bool check_updateable(char *db, char *table);

  void print(String *str);



  bool add_fake_select_lex(THD *thd);

  ulong init_prepare_fake_select_lex(THD *thd);

  int change_result(select_subselect *result, select_subselect *old_result);

  inline bool is_prepared() { return prepared; }

sql/sql_parse.cc

+57 −17
Original line number Diff line number Diff line
@@ -4189,23 +4189,9 @@ mysql_new_select(LEX *lex, bool move_down) 
  else

  {

    select_lex->include_neighbour(lex->current_select);

    SELECT_LEX_UNIT *unit= select_lex->master_unit();

    SELECT_LEX *fake= unit->fake_select_lex;

    if (!fake)

    {

      /*

	as far as we included SELECT_LEX for UNION unit should have

	fake SELECT_LEX for UNION processing

      */

      if (!(fake= unit->fake_select_lex= new(lex->thd->mem_root) SELECT_LEX()))

    if (!select_lex->master_unit()->fake_select_lex &&

        select_lex->master_unit()->add_fake_select_lex(lex->thd))

      return 1;

      fake->include_standalone(unit,

			       (SELECT_LEX_NODE**)&unit->fake_select_lex);

      fake->select_number= INT_MAX;

      fake->make_empty_select();

      fake->linkage= GLOBAL_OPTIONS_TYPE;

      fake->select_limit= HA_POS_ERROR;

    }

  }



  select_lex->master_unit()->global_parameters= select_lex;
@@ -4975,6 +4961,60 @@ void st_select_lex::set_lock_for_tables(thr_lock_type lock_type) 
}





/*

  Create a fake SELECT_LEX for a unit



  SYNOPSIS:

    add_fake_select_lex()

    thd			   thread handle



  DESCRIPTION

    The method create a fake SELECT_LEX object for a unit.

    This object is created for any union construct containing a union

    operation and also for any single select union construct of the form

    (SELECT ... ORDER BY order_list [LIMIT n]) ORDER BY ... 

    or of the form

    (SELECT ... ORDER BY LIMIT n) ORDER BY ...

  

  NOTES

    The object is used to retrieve rows from the temporary table

    where the result on the union is obtained.



  RETURN VALUES

    1     on failure to create the object

    0     on success

*/



bool st_select_lex_unit::add_fake_select_lex(THD *thd)

{

  SELECT_LEX *first_sl= first_select();

  DBUG_ENTER("add_fake_select_lex");

  DBUG_ASSERT(!fake_select_lex);

  

  if (!(fake_select_lex= new (thd->mem_root) SELECT_LEX()))

      DBUG_RETURN(1);

  fake_select_lex->include_standalone(this, 

                                      (SELECT_LEX_NODE**)&fake_select_lex);

  fake_select_lex->select_number= INT_MAX;

  fake_select_lex->make_empty_select();

  fake_select_lex->linkage= GLOBAL_OPTIONS_TYPE;

  fake_select_lex->select_limit= HA_POS_ERROR;



  if (!first_sl->next_select())

  {

    /* 

      This works only for 

      (SELECT ... ORDER BY list [LIMIT n]) ORDER BY order_list [LIMIT m],

      (SELECT ... LIMIT n) ORDER BY order_list [LIMIT m]

      just before the parser starts processing order_list

    */ 

    global_parameters= fake_select_lex;

    fake_select_lex->no_table_names_allowed= 1;

    thd->lex->current_select= fake_select_lex;

  }

  DBUG_RETURN(0);

}



void add_join_on(TABLE_LIST *b,Item *expr)

{

  if (expr)

sql/sql_select.cc

+1 −1
Original line number Diff line number Diff line
@@ -171,7 +171,7 @@ int handle_select(THD *thd, LEX *lex, select_result *result) 
  register SELECT_LEX *select_lex = &lex->select_lex;

  DBUG_ENTER("handle_select");



  if (select_lex->next_select())

  if (select_lex->next_select() || select_lex->master_unit()->fake_select_lex)

    res=mysql_union(thd, lex, result, &lex->unit);

  else

    res= mysql_select(thd, &select_lex->ref_pointer_array,