db={"user":[{"_id":1,"nombre":"n1"},{"_id":2,"nombre":"n2"},{"_id":3,"nombre":"n3"}],"trans":[{"user_id":1,"trans_tipo":"bank"},{"user_id":2,"trans_tipo":"bank"},{"user_id":3,"trans_tipo":"no"}]}

db.user.aggregate([{"$lookup":{"from":"trans","let":{"id":"$_id"},"pipeline":[{"$match":{"$expr":{"$and":[{"$eq":["$user_id","$$id"]},{"$eq":["$trans_tipo","bank"]}]}}}],"as":"trans"}},{"$match":{"trans":{"$ne":[]}}}])