db.dev_data_log.aggregate([{"$match":{"mid":"81100730","mfrsNo":"4","uploadAt":{"$gte":1522512000,"$lte":1557331199}}},
{"$group":{"_id":"$uploadDate","avgBatteryVoltage":{"$avg":"$batteryVoltage"}}},
{"$sort":{"uploadAt":-1}}])
1、查询的结果,不是按 uploadAt 倒序的;
2、查询的结果,并没有按过滤条件,返回 uploadAt 时间范围内的数据;