mysql“Access denied for user 'root'@'localhost'”问题的解决

我的Ubuntu系统最近使用mysql工具时，出现错误提示:

li@ubuntu:~$ mysql -uroot -p

Enter password: 

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

直接使用/etc/mysql/debian.cnf文件中[client]节提供的用户名和密码:

# mysql -u debian-sys-maint -p

Enter password: <输入[client]节的密码>

//mysql>登陆成功后修改user表

mysql>UPDATE user SET password='newpassword' WHERE user='root';

OK，已解决！重新登陆试一下：

#mysql -u root -p

Enter password:

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.1.49-1ubuntu8.1 (Ubuntu)

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.

This software comes with ABSOLUTELY NO WARRANTY. This is free software,

and you are welcome to modify and redistribute it under the GPL v2 license

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select user,host,password fromuser;

ERROR 1046 (3D000): No database selected

mysql> select user,host,password from mysql.user;

+------+-----------+----------+

| user | host      | password |

+------+-----------+----------+

| root | localhost | li       |

| li   | localhost | li       |

+------+-----------+----------+

2 rows in set (0.00 sec)