平时记录

1.将某时间字段数据进行减一天，然后赋值给其他时间字段列

update t_sg_spraygun_running c set c.day_time = DATE_SUB(c.create_time, INTERVAL 1 DAY) 

　　参考：cnblogs.com/geek233/p/16112906.html

2.某时间字段格式化后，重新赋值

update t_sg_spraygun_running c set c.create_time = date_format(create_time,'%Y-%m-%d 00:00:00') where id in(2, 72);