Le subquery si possono fare dalla versione 4.1.
Però:
http://dev.mysql.com/doc/refman/5.0/...trictions.html

In general, you cannot modify a table and select from the same table in a subquery. For example, this limitation applies to statements of the following forms:

DELETE FROM t WHERE ... (SELECT ... FROM t ...);
UPDATE t ... WHERE col = (SELECT ... FROM t ...);
{INSERT|REPLACE} INTO t (SELECT ... FROM t ...);
quindi se hai almeno la 4.1 e la subquery la fai su un'altra tabella si.