Database
[{"_id":ObjectId("5a934e000102030405000000"),"guild_id":1234,"members":[{"member_id":"001","name":"John Doe"},{"member_id":"002","name":"Bob"},{"member_id":"003","name":"Sam"}]}]
Query
db.collection.aggregate([{"$match":{"members.member_id":"001"}},{"$unwind":"$members"},{"$match":{"members.member_id":"001"}},{"$replaceWith":"$members"}])