mysql> explain SELECT i.*,m.preview_path FROM item_list i LEFT JOIN item_media m ON m.mid=i.mid WHERE m.media_type='flv' AND m.preview_path<>'' ORDER BY i.ilid DESC LIMIT 13;
+----+-------------+-------+------+---------------+------+---------+------+------+---------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+------+---------------+------+---------+------+------+---------------------------------+
| 1 | SIMPLE | i | ALL | NULL | NULL | NULL | NULL | 2697 | Using temporary; Using filesort |
| 1 | SIMPLE | m | ALL | NULL | NULL | NULL | NULL | 2697 | Using where |
+----+-------------+-------+------+---------------+------+---------+------+------+---------------------------------+
2 rows in set (0.00 sec)