Identifying the null values in a Collection

Hello Everyone,

I would like to identify the null values in the collection without using the specific key. For example in the below mentioned, without using the keys profession/education/etc., i want to get the list of the keys which are having null values across the collection. Is it possible to get the details as I need?

        "_id" : ObjectId("528f22140fe5e6467e58ae73"),
        "user_id" : "user1",       
        "sex" : "Male",
        "age" : 17,
        "date_of_join" : "16/10/2010",
        "education" : "M.C.A.",
        "profession" : "CONSULTANT",
        "interest" : "MUSIC"
        "_id" : ObjectId("528f222e0fe5e6467e58ae74"),
        "user_id" : "user2",
        "sex" : null,
        "age" : 24,
        "date_of_join" : "17/10/2009",
        "education" : "M.B.A.",
        "profession" : "MARKETING",
        "interest" : null
        "_id" : ObjectId("528f22390fe5e6467e58ae75"),
        "user_id" : "user3",
        "sex" : "Female",
        "age" : 19,
        "date_of_join" : "16/10/2010",
        "education" : "M.C.A.",
        "profession" : null,
        "interest" : "ART"
        "_id" : ObjectId("528f22430fe5e6467e58ae76"),
        "user_id" : "user4",
        "sex" : "Female",
        "age" : 22,
        "date_of_join" : "17/8/2009",
        "education" : null,
        "profession" : "DOCTOR"

Have you solve your other issue:

If you did share the solution or mark one of the reply as the solution.

This following post also needs closure:

As mentioned in your other posts:

Can any one provide the inputs for this query?

I will give you a hint. Look at $objectToArray then $match on v : null.

But that is all I will give you until you do your part to keep this forum useful. And your part is to supply closure for your other threads as requested in my previous post.