Realmのデータ取得時にNSDateの条件を指定する方法

結論

NSPredicateを使う。

NSPredicate *pred = [NSPredicate predicateWithFormat:@"createdAt < %@", date];
RLMResults *results = [RealmModel objectsWithPredicate:pred];

objectsWhereだとうまくいかない

NSString *query = [NSString stringWithFormat:@"createdAt < %@", date];
RLMResults *results = [RealmModel objectsWhere:query];

↑でやると↓が出て落ちる。

Terminating app due to uncaught exception 'Invalid value', reason: 'Expected object of type date for property 'createdAt' on object of type 'RealmModel', but received: 2015-11-01 00:00:00 +0000'