I’m using Realm in a Swift project to store my data. I want to use the Realm Swift Query API to query object attributes contained in a List.

My (simplified) objects look like:

open class QuestionModel: Object {
    
    @objc dynamic var uuid: String!
    override public static func primaryKey() -> String? {
        return "uuid"
    }
    // attributes about the media for this question are wrapped up in a MediaModel object
    @objc dynamic var media: MediaModel?
    
}

open class MediaModel: Object {
    // A question can have up to two ImageModels    
    open var images = List<ImageModel>()

}

open class ImageModel: Object {
    // The filename on disk to use to create a UIImage
    @objc dynamic var filename: String? = nil
    // an description of the image
    @objc dynamic var altDescription: String? = nil
   
}

In some circumstances I want to only get QuestionModels where the first ImageModel.filename != “”

Here’s what I’ve tried:

res = realm?.objects(QuestionModel.self)

and I want to further filter the QuestionModels based on certain criteria

Using NSPredicate and Subquery seems to work, though I don’t think it understands which image.name is blank, it just gives me all questions where one of the image.filenames is filled in

res = res.filter("SUBQUERY(media.images, $image, $image.name != '').@count > 0")

However, I really want to move to the new Realm Swift Query API if possible.

res = res.where {
                $0.media.images.name != ""
            }

Gives NSException * “Key paths that include a collection property must use aggregate operations”

res = res.where {
           ($0.media.images.name != "").count > 0
        }

Give NSException * “Subqueries must contain a keypath starting with a collection.”

I’m very confused. I can’t seem to find an example online which makes me wonder if this is possible.
Any thought appreciated