MySQL用户权限

grant all privileges on db.* to 'user'@'%' identified by 'pwd' -- with grant option;

Revoke all on *.* to 'z'@'%' identified by 'Z';
revoke all on *.* from 'z'@'%'

show grants for 'z'@'%';

update mysql.proc set definer='z@%' where db='n'