Database
[{"_id":"fGR4ECcw5p2HFgxd3","ownerId":"J8MpsWChPQdET6jwQ","inventory":[{"_id":ObjectId("5b537ef5895adfeae037e0a4"),"quantity":17},{"_id":ObjectId("5b537d9c895adfeae037dbd2"),"quantity":6},{"_id":ObjectId("5b5868e081702f675304290e"),"quantity":26},{"_id":ObjectId("5b5eba8276dd90bd75e27f13"),"quantity":85},{"_id":ObjectId("5b5ee58176dd90bd75e2f35f"),"quantity":5},{"_id":ObjectId("5b62275686f92e050a9d50b2"),"quantity":3}]}]
Query
db.collection.find({ownerId:"J8MpsWChPQdET6jwQ"},{inventory:{$elemMatch:{_id:ObjectId("5b537ef5895adfeae037e0a4")}}})