Compare data between collections

Hello Everyone,

I’m trying to compare the data between two similar collections,

Collection1 : Employee
Emp_id, First_Name,Last_Name,Phone,Address,e-mail

Collection2 : Employee_Test
Emp_id, First_Name,Last_Name,Phone,Address,e-mail

I would need to write the mongo query to compare the data between these two to find

  1. Difference in data
  2. Union between these two collections to display the comparsion, this would be a comparison document wise just like a row wise comparison in SQL datatabase.

Any suggestions or guidance would be highly appreciated.

Thanks in advance,

My first step would be to use $lookup on Emp_id. Then using $cond to compared the fields.