您可以使用 DATE_ADD（）：

  DATE_ADD（my_date，INTERVAL 30 DAY）
 

I have publish up date and publish down date in my DB. Currently they are both same dates.

How do I change it (during mysql insert) so publish down date is 30 days past publish up date.

I am using $pubDate

Thanks

You can use DATE_ADD():

DATE_ADD(my_date, INTERVAL 30 DAY)