centos安装mysql时未设置root密码，导致无法登录

# /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> 

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>