This automaticly makes EXPLAIN EXTENDED a lot more useful as we see how it rewrites our queries:
root@127.0.0.1:3306 []> EXPLAIN EXTENDED SELECT (SELECT 1);
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
| 1 | PRIMARY | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | No tables used |
+----+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+
OK (warnings: 2, auto-commit: true)
+-------+------+------------------------------------------+
| Level | Code | Message |
+-------+------+------------------------------------------+
| Note | 1249 | Select 2 was reduced during optimization |
| Note | 1003 | SELECT 1 AS `(SELECT 1)` |
+-------+------+------------------------------------------+
OK (warnings: 0, auto-commit: true)