用滚动平均列更新mysql表，意外地更新了时间戳

Question

这是我的桌子：

CREATE TABLE IF NOT EXISTS Data(
                    Time TIMESTAMP(3),
                    Ms1 FLOAT,
                    Ms1roll FLOAT)

计算滚动平均值之前的数据示例为：

 Time                    | Ms1     | Ms1roll |
+-------------------------+----------+---------
| 2019-11-16 21:26:56.248 | 22.4398 |    NULL | 
| 2019-11-16 21:27:08.251 | 22.4513 |    NULL | 
| 2019-11-16 21:27:20.231 | 22.4515 |    NULL | 
| 2019-11-16 21:27:32.245 | 22.4513 |    NULL | 
| 2019-11-16 21:27:44.245 | 22.4515 |    NULL | 
| 2019-11-16 21:27:56.251 | 22.4514 |    NULL | 
....

我想计算时间与时间之间的滚动平均值-6分钟。 我尝试过：

A：

update Data set Ms1roll=select b.avg from (select temp.avg,temp.Time FROM (select Data.Time, Data.Ms2, avg(Data_past.Ms1) as avg from Data join Data as Data_past on Data_past.Time between Data.Time - INTERVAL 6 MINUTE and Data.Time group by 1, 2) as temp) as b  where b.Time=Data.Time;

B：

update Data as t1
INNER JOIN (select temp.avg,temp.Time FROM (select Data.Time, Data.Ms2, avg(Data_past.Ms1) as avg from Data join Data as Data_past on Data_past.Time between Data.Time - INTERVAL 6 MINUTE and Data.Time group by 1, 2) as temp) as t2 on t2.Time=t1.Time set t1.Ms1Roll=t2.avg

我得到：

+-------------------------+----------+---------+
| Time                    | Ms1     | Ms1roll | 
+-------------------------+----------+---------+
| 2019-11-16 21:32:43.633 | 22.4398 | 22.4398 | 
| 2019-11-16 21:32:43.633 | 22.4513 | 22.4455 | 
| 2019-11-16 21:32:43.633 | 22.4515 | 22.4475 | 
| 2019-11-16 21:32:43.633 | 22.4513 | 22.4485 |
| 2019-11-16 21:32:43.633 | 22.4515 | 22.4491 |
| 2019-11-16 21:32:43.633 | 22.4514 | 22.4495 | 
...

为什么时间戳会更改？

感谢您的帮助， 查理。