I need to check to see whether two users are friends using FQL.
If this query returns a result,
user2 are friends:
SELECT uid1 FROM friend WHERE uid1 = $user1 AND uid2 = $user2;
There are no privacy restrictions on this query in terms of errors, but you
will get back an empty set if the current
loggedinuser isn’t allowed to see the
friends for one of the two users.