mysql> explain select * from sakila.film join sakila.film_actor using(film_id) where sakila.film.film_id = 1; +----+-------------+------------+-------+----------------+----------------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+-------+----------------+----------------+---------+-------+------+-------+ | 1 | SIMPLE | film | const | PRIMARY | PRIMARY | 2 | const | 1 | | | 1 | SIMPLE | film_actor | ref | idx_fk_film_id | idx_fk_film_id | 2 | const | 10 | | +----+-------------+------------+-------+----------------+----------------+---------+-------+------+-------+ 2 rows in set (0.00 sec) mysql> notee