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

You can do it in one go using mongo-join-query. Here is how it would look like:

const joinQuery = require("mongo-join-query");

joinQuery(
    mongoose.models.User,
    {
        find: {},
        populate: ["friends"],
        sort: { age: 1 },
    },
    (err, res) => (err ? console.log("Error:", err) : console.log("Success:", res.results))
);

The result will have your users ordered by age and all of the friends objects embedded.

How does it work?

Behind the scenes mongo-join-query will use your Mongoose schema to determine which models to join and will create an aggregation pipeline that will perform the join and the query.