多表修改：
update t_user u
inner join t_student s
on s.u_id=u.id
set u.password=‘zhangsan1243‘,s.teacher=‘hehe‘
where u.card=‘zhangsan123‘;
多表删除：
delete u,t from t_user u
inner join t_student s
on s.u_id=u.id
where u.card=‘zhangsan123‘;
原文：https://www.cnblogs.com/kongnengjing/p/9452520.html