"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> EXISTS works in situations where
> you need to compare on multiple columns, so it is useful in many
> situations where IN or MIN/MAX techniques just don't work.
IN works fine on multiple columns:
(foo, bar, baz) IN (SELECT x, y, z FROM ...)
regards, tom lane