Database
db={"skills":[{"_id":"627092699d087d0e7db4f359","Skill":"AdSense Tracker","Date":"2022-05-03T02:23:01.611Z"}],"userskill":[{"_id":"62a39c6f2a73b0cc3af71e56","userID":"625decf49b367400701f6f67","skillID":"627092699d087d0e7db4f359"},{"_id":"62a39c6f2a73b0cc3af71e58","userID":"625decf49b367400701f6f67","skillID":"627092699d087d0e7db4f35c"},{"_id":"62a39c702a73b0cc3af71e5a","userID":"625decf49b367400701f6f67","skillID":"627092699d087d0e7db4f35d"}]}
Query
db.userskill.aggregate([{$lookup:{from:"skills",localField:"skillID",foreignField:"_id",as:"skill",},},])