Somebody asked me about this a few days ago, and this person (really sure of what he was talking about) told me: "You can only pass a limit of 200 items in a IN clause (during a DELETE)"
I'm not an Expert DBA (know it all), but I do remember that you can pass up to 1000 elements. And that was my counter argument to this guy (as always if you don't believe me double check with your best friend or test it
In the past it used to be 256 elements, but that was in Oracle 8.
