Fetched Properties inside NSFetchedResultsController's predicate

I have an Artist object with a .localConcerts fetched property (basically a subset of the full .concerts set), can I use that property inside my NSFetchedResultsController predicate?

Here's what I'm trying:

NSFetchRequest *request = [[NSFetchRequest alloc] init];

NSEntityDescription *entity = [NSEntityDescription entityForName:@"Artist" inManagedObjectContext:context];
[request setEnti开发者_StackOverflow社区ty:entity];

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"localConcerts.@count > 0"];
[request setPredicate:predicate];

fetchedResultsController = [[NSFetchedResultsController alloc]
                            initWithFetchRequest:request
                            managedObjectContext:context
                            sectionNameKeyPath:nil
                            cacheName:nil];

But I'm getting:

'keypath localConcerts not found in entity <NSSQLEntity Artist id=1>'

Am I missing anything or is it just not possible to use fetched properties inside predicates?

Apparently NSPredicate can only filter using attributes that are in the database structure (this makes sense). In my case, using a subquery did the trick:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SUBQUERY(shows, $show, $show.distance < %@).@count > 0", [SWDataManager sharedManager].localFilterDistance];

I had no idea we could do subqueries in NSPredicate, that's great to know. Credits go to @kyleve.