New EXISTS() functionality in 5.5?

[Eric McNeill]

On the web I find lots of discussions about how this typical SQL Server sproc syntax doesn't work on MySQL:

IF EXISTS(SELECT * FROM Foo WHERE Bar = 'x') THEN
-- do something
END IF;

However I'm finding that on MySQL 5.5.8 it works just fine. Is EXISTS() used in this context a new feature in 5.5? In the docs I see it mentioned as being used in subqueries or as part of statements such as CREATE DATABASE, but it seems to stand on its own, e.g.

SET @x = EXISTS(Select * FROM Foo);

This would be a great boon to those out there using count(*) for this sort of thing.

Eric