mysql时间(datetime)精确到毫秒

https://blog.csdn.net/qq_33862644/article/details/83744416

ALTER TABLE device_upgrade_info MODIFY COLUMN start_time DATETIME(3);

TIMESTAMP(3)与 DATETIME(3)意思是保留3位毫秒数

TIMESTAMP(6)与 DATETIME(6)意思是保留6位毫秒数