There may be instances where you need to update several row date columns with one query. For example, if you need to extend out an ‘expire_date’ column by 30 days. Example:


UPDATE <some_table> SET expire_date = adddate(now(), interval 30 DAY) WHERE <some_criteria>;

You can find more MySQL date functions @ http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html