mysql> explain select * from sakila.film_actor join sakila.film using(film_id); +----+-------------+------------+------+----------------+----------------+---------+---------------------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+------+----------------+----------------+---------+---------------------+------+-------+ | 1 | SIMPLE | film | ALL | PRIMARY | NULL | NULL | NULL | 952 | | | 1 | SIMPLE | film_actor | ref | idx_fk_film_id | idx_fk_film_id | 2 | sakila.film.film_id | 2 | | +----+-------------+------------+------+----------------+----------------+---------+---------------------+------+-------+ 2 rows in set (0.00 sec) mysql> notee