iPhone predicate: One of each.

Question

I was wondering if it was possible to run a query using a predicate specifying "one of each." They do not seem to have anything similar to this in the predicate documentation.

Appreciate any help or resources.

UPDATE: I want to return every unique instance in a column which contains duplicates.

Answer 1

Take the results of your NSPredicate and put them into an NSSet (or its mutable child NSMutableSet). By definition, a set contains no duplicates.