How to join query in mongodb?

Question

I have user document collection like this:

User {
   id:\"001\"
   name:\"John\",
   age:30,
   friends:[\"userId1\",\"userId2\",\"userId3\"....]
}
         


        

Answer 1

https://docs.mongodb.org/manual/reference/operator/aggregation/lookup/

This is the doc for join query in mongodb , this is new feature from version 3.2.

So this will be helpful.