[{"_id":"5f9d42a0a8e71e004643f584","user":{"_id":"5f7308cde0a4a7a66bc3d184","name":"Guest"},"room":{"_id":"5f98f9321fd5bb0045b3d886","name":"100",},"rating":4,},{"_id":"5f9d431ea8e71e004643f585","user":{"_id":"5f7308cde0a4a7a66bc3d184","name":"Guest",},"room":{"_id":"5f98f9321fd5bb0045b3d886","name":"100",},"rating":5,},{"_id":"5f9e74fea6c06a0046d3cae2","user":{"_id":"5f7308cde0a4a7a66bc3d184","name":"Guest",},"room":{"_id":"5f98fa8b1fd5bb0045b3d88a","name":"300",},"rating":5,}]

db.collection.find({"room.name":"100"})