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Fixed bug #18767.

Browse Source 
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. 


mysql-test/r/order_by.result:
  Added a test case for bug #18767.
mysql-test/t/order_by.test:
  Added a test case for bug #18767.
sql/sql_lex.h:
  Fixed bug #18767.
  Placed the code the created a fake SELECT_LEX into a separate function.
sql/sql_parse.cc:
  Fixed bug #18767.
  Placed the code the created a fake SELECT_LEX into a separate function.
sql/sql_select.cc:
  Fixed bug #18767.
  Changed the condition on which a SELECT is treated as part of a UNION.
  The SELECT in 
  (SELECT ... ORDER BY order_list1 [LIMIT n]) ORDER BY order_list2 
  now is handled in the same way as the first SELECT in a UNION
  sequence.
sql/sql_union.cc:
  Fixed bug #18767.
  Changed the condition at which a SELECT is treated as part of a UNION.
  The SELECT in 
  (SELECT ... ORDER BY order_list1 [LIMIT n]) ORDER BY order_list2 
  now is handled in the same way as the first SELECT in a UNION
  sequence.
sql/sql_yacc.yy:
  Fixed bug #18767.
  Changed the condition at which a SELECT is treated as part of a UNION.
  The SELECT in 
  (SELECT ... ORDER BY order_list1 [LIMIT n]) ORDER BY order_list2 
  now is handled in the same way as the first SELECT in a UNION
  sequence. In the same way is handled the SELECT in
  (SELECT ... LIMIT n) ORDER BY order list.
  Yet if there is neither ORDER BY nor LIMIT in the single-select
  union construct
  (SELECT ...) ORDER BY order_list
  then it is still handled as simple select with an order clause.
This commit is contained in:
unknown
2006-04-20 22:15:38 -07:00
parent d7055274ed
commit 9225a51c58
7 changed files with 127 additions and 22 deletions
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74
sql/sql_parse.cc
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@@ -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()))
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;
}
if (!select_lex->master_unit()->fake_select_lex &&
select_lex->master_unit()->add_fake_select_lex(lex->thd))
return 1;
}
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)