database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MDEV-9513: Assertion `join->group_list || !join->is_in_subquery()' failed in create_sort_index

Browse Source 
Removing the ORDER BY clause from the UNION when UNION is inside an IN/ALL/ANY/EXISTS subquery.
The rewrites are done for subqueries but this rewrite is not done for the fake_select of
the UNION.
This commit is contained in:
Varun Gupta
2020-08-04 14:36:01 +05:30
parent 0e80f5a693
commit ab578bdf45
4 changed files with 89 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
sql/sql_union.cc
View File

@ -388,6 +388,25 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
found_rows_for_union= first_sl->options & OPTION_FOUND_ROWS;
is_union_select= is_union() || fake_select_lex;
/*
If we are reading UNION output and the UNION is in the
IN/ANY/ALL/EXISTS subquery, then ORDER BY is redundant and hence should
be removed.
Example:
select ... col IN (select col2 FROM t1 union select col3 from t2 ORDER BY 1)
(as for ORDER BY ... LIMIT, it currently not supported inside
IN/ALL/ANY subqueries)
(For non-UNION this removal of ORDER BY clause is done in
check_and_do_in_subquery_rewrites())
*/
if (is_union() && item &&
(item->is_in_predicate() || item->is_exists_predicate()))
{
global_parameters()->order_list.first= NULL;
global_parameters()->order_list.elements= 0;
}
/* Global option */
if (is_union_select)