Firebase query in iOS swift

This is my first screenshot database in firebase:

This is my second screenshot database in firebase:

I am able to retrieve data from firebase also set in table view. But I want all data that which first screenshot database key (1album) equal to second database post_key: 1album.

I tried like this:

refhandel = ref.child("SongPlay").child("1album"] ).queryOrdered(byChild:"post_key").observe(.childAdded, with: { (snapshot) in

if let item = snapshot.value as? [String: AnyObject]{

            let music = MusicDataModel()
            music.setValuesForKeys(item)
            MusicData.append(music)
   }
})