mysql> explain SELECT a.id account_id, e.item_type, e.default, d.amount, SUM(b.duration) FROM accounts a RIGHT JOIN call_log b ON (a.id = b.account_id) RIGHT JOIN accounts_items c ON (a.id = b.account_id) RIGHT JOIN items_call_rates d ON (c.id = d.item_id) LEFT JOIN items e ON (c.reference_id = e.id) GROUP BY e.item_type;
+----+-------------+-------+--------+---------------+---------+---------+----------------------+-------+---------------------------------+
| id | select_type | table | type   | possible_keys | key     | key_len | ref                  | rows  | Extra                           |
+----+-------------+-------+--------+---------------+---------+---------+----------------------+-------+---------------------------------+
|  1 | SIMPLE      | d     | ALL    | NULL          | NULL    | NULL    | NULL                 |    13 | Using temporary; Using filesort |
|  1 | SIMPLE      | c     | eq_ref | id            | id      | 8       | table.d.item_id      |     1 |                                 |
|  1 | SIMPLE      | a     | index  | PRIMARY,id    | PRIMARY | 8       | NULL                 |   200 | Using index                     |
|  1 | SIMPLE      | b     | ALL    | NULL          | NULL    | NULL    | NULL                 | 54848 |                                 |
|  1 | SIMPLE      | e     | eq_ref | id            | id      | 8       | table.c.reference_id |     1 |                                 |
+----+-------------+-------+--------+---------------+---------+---------+----------------------+-------+---------------------------------+
5 rows in set (0.00 sec)