[{"name":"a","artist_id":1,"is_song":1,"is_soundtrack":0,"count":2},{"name":"a","artist_id":1,"is_song":1,"is_soundtrack":0,"count":1},{"name":"a","artist_id":2,"is_song":1,"is_soundtrack":0,"count":1},]

db.collection.aggregate([{"$match":{"is_song":1,"is_soundtrack":0}},{"$group":{"_id":{"name":"$name","artist_id":"$artist_id"},"count":{"$sum":1}}},{$match:{"count":{"$gt":1}}},{"$sort":{"count":-1}}])