gistfile1.txt

mysql> select * from items;
+------+----+
| name | id |
+------+----+
| aaa  |  1 | 
| bbb  |  2 | 
| ccc  |  3 | 
| ddd  |  4 | 
+------+----+
4 rows in set (0.00 sec)

mysql> select * from tags; 
+------+----+
| name | id |
+------+----+
| tag1 |  1 | 
| tag2 |  2 | 
+------+----+
2 rows in set (0.00 sec)

mysql> select * from items_tags;
+---------+--------+
| item_id | tag_id |
+---------+--------+
|       1 |      1 | 
|       2 |      1 | 
|       2 |      2 | 
|       3 |      2 | 
+---------+--------+
4 rows in set (0.00 sec)

mysql> select i.name, t1.name, t2.name from items i join items_tags it1 on it1.item_id = i.id join tags t1 on it1.tag_id = t1.id join items_tags it2 on it2.item_id = i.id join tags t2 on it2.tag_id = t2.id where t1.name = 'tag1' and t2.name = 'tag2';
+------+------+------+
| name | name | name |
+------+------+------+
| bbb  | tag1 | tag2 | 
+------+------+------+
1 row in set (0.00 sec)