[{"_id":1,"name":"John","age":25,"valid_user":true},{"_id":2,"name":"Bob","age":40,"valid_user":false},{"_id":3,"name":"Jacob","age":27,"valid_user":null},{"_id":4,"name":"Amelia","age":29,"valid_user":true}]

db.collection.aggregate([{"$facet":{"user_by_valid_status":[{"$group":{"_id":"$valid_user","count":{"$sum":1}}}],"users_above_30":[{"$match":{"age":{"$gt":30}},}]}}])