mysql日期加减问题

有一个date列，我想修改下，
让该列里每个日期都加上7天，怎么写代码？ 

update [表名] set  date=date_add(date, interval 7 day);

SELECT * from game_user gu, card c WHERE gu.id = c.game_user_id and c.card_id = 326 and date_add(DATE_FORMAT(gu.enroll_time,'%Y-%m-%d'), interval gu.continue_login_days day) = DATE_FORMAT(gu.last_stamp,'%Y-%m-%d') and gu.login_days >= 7 ORDER BY gu.id

-- SELECT * from game_user gu WHERE date_add(DATE_FORMAT(gu.enroll_time,'%Y-%m-%d'), interval gu.continue_login_days day) = DATE_FORMAT(gu.last_stamp,'%Y-%m-%d') and gu.login_days >= 7 ORDER BY gu.id