I'd suggest keeping it

Oh, it'll stay for a while. At least until I've upgraded my own production systems to a more recent mysql (or better yet: something that isn't mysql). It'll certainly be removed when big changes happen, though. And - if you really want to depend on this feature (note that it cannot be fast and that it cannot be atomic), it's not too hard to copy the code now and subclass DBIx::Simple when the time comes. Actually, maybe I'll do so myself and release that.

Update - It'll be in DBIx::Simple::SQE.

Update - In March 2007, with DBIx::Simple release 1.27, support for subquery emulation was dropped completely.