创建新用户，刷新赋权限

删除用户：
delete from user where user="0" or user=null;
删除用户名为空和为0的用户。
添加mysql系统用户
GRANT ALL PRIVILEGES ON [dbname].* to
'[user]'@'[hostname]' identified by
'[password]'

添加一个用户
GRANT SELECT,INSERT,UPDATE,DELETE,DROP
on test.*
to `test`@`localhost`
identified by "test";
Query OK, 0 rows affected (0.00 sec)

mysql> select host,user from user;
+-----------+----------------+
| host      | user           |
+-----------+----------------+
| %         |                |
| 127.0.0.1 | root           |
| localhost | hello|
| localhost | root           |
| localhost | test           |
+-----------+----------------+
5 rows in set (0.00 sec)

插入数据后腰执行下面刷新语句。
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)