Database
[{_id:"ObjectId1",status:"WAITING","members":["ID1"]},{_id:"ObjectId2",status:"WAITING","members":["ID2"]},{_id:"ObjectId3",status:"ENDED","members":["ID1","ID2"]}]
Query
/**db.collection.find({members: {$elemMatch: {"ID2"}}})*/db.collection.find({status:"ENDED",members:{$elemMatch:{$eq:"ID2"}}})