如何修改mysql的用户名和密码

mysql -u root -p
Enter password：***
mysql>use mysql;  选择数据库
Database changed 
mysql> UPDATE user SET password=PASSWORD("新密码") WHERE user='你的用户名';
mysql> FLUSH PRIVILEGES;
mysql> quit;

mysql -u root -p
Enter password：***
mysql> use mysql;  选择数据库
Database changed
mysql> update user set user="新用户名" where user="root";    将用户名为root的改为新用户名
mysql> flush privileges;    刷新权限
mysql> exit