宮川です。

http://www.mysql.com/press/release_2003_05.html

Subselects Add Advanced Querying Capabilities

MySQL Version 4.1 includes support for SQL subselects, also called
subqueries or nested queries, a powerful feature that lets users
search complex data with ease and efficiency. With subselects, users
can achieve query consolidation by nesting one query inside another
query, creating a resource otherwise unavailable for searching in a
single statement. Subselects allow users to query within a result set,
creatively limit the result set or correlate results with an otherwise
unrelated query in a single call to the database.

というわけで alpha ではありますが sub-query がつかえるようになってますね。


-- 
Tatsuhiko Miyagawa <miyagawa@xxxxxxxxxx>