Not that I want to encourage bad habits, but I seem to recall a discussion (I thought it was here @ SQL Server Central, but I can't find it) regarding COUNT(*) vs EXISTS, and tests were carried out (in SQL 2005 or 2008) where the compiler was smart enough to recognize that a programmer really intended to use EXISTS not COUNT(*), and so actually generated the same execution plan for both - the SQL Server engineering team compensating for the huge amount of abuse of COUNT(*) that goes on.

...But as I said, that's still no excuse for bad programming - the right tool for the job is EXISTS

EDIT: :blush: Forgot to say 'thanks for the cool list of things to look out for' - so, David, thanks for the cool list of things to look out for 😀