一、现象：       公司linux系统的mysql数据库root用户设置过密码，但常常用命令‘mysql -u root -p‘登录报错，有时又能登录。登录报错信息为：[root@localhost ~]# mysql -u root -pEnter password: ERROR 1045 (28000): Access denied for user ‘root‘@‘localhost‘ (using password: YES)二、原因：数据库中存在空用户所致三、处理办法：1、停用mysql服务：# service mysql stop2、输入命令：# mysqld_safe --user=mysql --skip-grant-tables --skip-networking & 3、登入数据库：# mysql -u root mysql4、mysql> use mysql;5、mysql> select user,host,password from user; 结果如下：+------+-----------------------+----------+| user | host                  | password |+------+-----------------------+----------+| root | %                           | mima  || root | localhost.localdomain | mima  || root | 127.0.0.1                 | mima  ||        | localhost                  |          ||        | localhost.localdomain |          |+------+-----------------------+----------+6、将上面查询出来的空用户删除：mysql> delete from user where user=‘‘;7、退出数据库：mysql> quit8、启动mysql服务：# service mysql start9、重新用命令‘mysql -u root -p’登录，OK！