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

15 lines
1.1 KiB
SQL

explain
select actor_id,
(select count(film_id) from sakila.film join sakila.film_actor using(film_id))
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 |
| 2 | SUBQUERY | film | index | PRIMARY | idx_fk_language_id | 1 | NULL | 951 | Using index |
| 2 | SUBQUERY | film_actor | ref | idx_fk_film_id | idx_fk_film_id | 2 | sakila.film.film_id | 2 | Using index |
+----+-------------+------------+-------+----------------+--------------------+---------+---------------------+------+-------------+
3 rows in set (0.00 sec)
mysql> notee