mysql> explain select actor_1.actor_id from sakila.actor as actor_1 inner join sakila.actor as actor_2 using(actor_id) inner join sakila.actor as actor_3 using(actor_id);
+----+-------------+---------+--------+---------------+---------+---------+-------------------------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+---------+--------+---------------+---------+---------+-------------------------+------+-------------+
| 1 | SIMPLE | actor_1 | index | PRIMARY | PRIMARY | 2 | NULL | 200 | Using index |
| 1 | SIMPLE | actor_2 | eq_ref | PRIMARY | PRIMARY | 2 | sakila.actor_1.actor_id | 1 | Using index |
| 1 | SIMPLE | actor_3 | eq_ref | PRIMARY | PRIMARY | 2 | sakila.actor_1.actor_id | 1 | Using index |
+----+-------------+---------+--------+---------------+---------+---------+-------------------------+------+-------------+
3 rows in set (0.00 sec)
mysql> notee
|