mongodb joins are not working when two collections joined with ObjectId method

[anil741]

mongodb joins are not working when two collections joined with ObjectId method.

When i am trying to join the one parent collection with another collection i.e; another collection contains parent collection id in the format of ObjectId. In this case the data is not getting.

But if i try to change the ObjectId to string, then i can see the proper results.

Can any one please help me out of these issue?