系统默认的MySQL用户名消失的解决方法

系统默认的MySQL用户名消失的解决方法2010-07-07修改MySQL下的默认mysql数据库的user表，删除所有host为localhost记录，另外添加一些其他记录，重新启动MySQL服务器。执行show databases，只出现information_schema和test两个数据库，看不到mysql。

解决方法：

此问题实际上是用户没有权限：

1. 关闭mysql

2. 启动mysql： mysqld_safe --skip-grant-tables

在数据库名mysql下的user表中，修改相应权限，比如：

INSERT INTO `user` VALUES （"localhost","root","","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y","Y"