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percona-toolkit/t/pt-visual-explain/samples/adjacent_subqueries.sql
2011-06-24 16:02:05 -06:00

15 lines
1.2 KiB
SQL

explain
select (
select count(*) from sakila.film_actor
where sakila.film_actor.actor_id = sakila.actor.actor_id
) + (
select count(*) from sakila.film as f
) as count_actors from sakila.actor;
+----+--------------------+------------+-------+---------------+--------------------+---------+----------------+------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+--------------------+------------+-------+---------------+--------------------+---------+----------------+------+--------------------------+
| 1 | PRIMARY | actor | index | NULL | PRIMARY | 2 | NULL | 200 | Using index |
| 3 | SUBQUERY | f | index | NULL | idx_fk_language_id | 1 | NULL | 951 | Using index |
| 2 | DEPENDENT SUBQUERY | film_actor | ref | PRIMARY | PRIMARY | 2 | actor.actor_id | 13 | Using where; Using index |
+----+--------------------+------------+-------+---------------+--------------------+---------+----------------+------+--------------------------+