mysql中出现Access denied for user ‘root’@’localhost’ (using password: YES)

今天在启动mysql时出现以下问题：

[root@www ~]# mysql -u root -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

网上的答案是各种各样的，最终解决问题的方法总结为以下，好多都是没有设置初始密码造成此问题的。

解决方法如下：

[root@www ~]# service mysqld  stop      #先关闭mysql服务
Stopping mysqld:                                           [  OK  ]

[root@www ~]# mysql
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
[root@www ~]# mysql -u  root  -p           #关闭服务后又出现如下问题
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

[root@www ~]# mysql -u root  mysql       #键入此命令进入mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.73 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> update user set password=password('123') where user='root' and host='localhost';   ---->修改root的密码
Query OK, 1 row affected (0.04 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> flush priviledge;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'priviledge' at line 1
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> \q
Bye
[root@www ~]# mysql -u root  -p                     ------>重新进入
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.1.73 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> \q
Bye

到此就完了！！