mysql 报错权限拒绝

异常：
# mysql -uroot -p
Enter password:
ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: NO)

方法一：

# /etc/init.d/mysql stop
# mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
# mysql -u root mysql
mysql> UPDATE user SET Password=PASSWORD('newpassword') where USER='root';
mysql> FLUSH PRIVILEGES;
mysql> quit

# /etc/init.d/mysql restart
# mysql -uroot -p

Enter password: <输入新设的密码newpassword>

mysql>

方法二：

直接使用/etc/mysql/debian.cnf文件中[client]节提供的用户名和密码:
# mysql -udebian-sys-maint -p
Enter password: <输入[client]节的密码>
mysql> UPDATE user SET Password=PASSWORD('newpassword') where USER='root';
mysql> FLUSH PRIVILEGES;
mysql> quit
# mysql -uroot -p
Enter password: <输入新设的密码newpassword>

mysql>