1、初始安装时.从日志中查找root默认密码

2.登录root，修改密码

  alter user 'root'@'localhost' identified by '123';

  alter user 'root'@'%' identified by '123';

3.创建用户并授权

   CREATE USER 'admin' IDENTIFIED BY 'admin';

    grant all privileges on *.* to 'admin'   with grant option;