Realm Swift: Filtering objects by nested List property using IN predicate

Question

I have the following Realm Object structure:

class ParentObject: Object {
    let nestedObjects = List<NestedObject>
}

class NestedObject: Object {
    @objc dynamic var id: Int = 0
}

Is it possible to filter ParentObjects to return only those that contain NestedObjects whose id matches one of those contained in an array?

I tried doing it this way:

let ids = [1, 2, 3]

let filtered = realm
    .objects(ParentObject.self)
    .filter("nestedObjects.id IN %@", ids)

But I'm getting this error: Terminating app due to uncaught exception 'Invalid predicate', reason: 'Key paths that include an array property must use aggregate operations'.

Maybe I should try doing it with multiple ORs instead of IN?

Answer 1

You want a predicate of ANY nestedObjects.id IN %@. The ANY/ALL/NONE modifier is important as it determines how many of the objects in the collection must match for the predicate to evaluate to true.

Answer 2

new realm safe query syntax (10.19 I think) : example looking for all parents with a nested object with id = myID and with a type = myType

let filtered = realm
        .objects(ParentObject.self)
        .where ({ parent in
            parent.nestedObjects.id == myId &&
            parent.nestedObjects.type == myType
        })

with old predicate syntax :

let filtered = realm
        .objects(ParentObject.self)
        .filter("ANY nestedObjects.id IN %@", [myId])
        .filter("ANY nestedObjects.type IN %@)", [myType])