设置mysql可以外网链接

先看最后的解释
//设置为远程可以访问
下面代码为小编解决该问题的方法：
:Program Filesmysql-5.5.25in>mysql -u root -p
Enter password: ******
mysql> use mysql;

mysql> select host,user,password from user;

| localhost | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| 127.0.0.1 | root | |
| ::1 | root | |
| localhost | | |

mysql> update user set host='%' where user='root';
ERROR 1062 (23000): Duplicate entry '%-root' for key 'PRIMARY'

mysql> select host,user from user where user='root';

| % | root |
| 127.0.0.1 | root |
| ::1 | root |

mysql> flush privileges;

mysql> quit;
Bye
//再进入会错
MySQL 服务已经启动成功。
D:Program Filesmysql-5.5.25in>mysql -u root -p
Enter password: ******
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
D:Program Filesmysql-5.5.25in>mysql -u root -p
Enter password:
mysql> exit;
Bye
//重设密码
D:Program Filesmysql-5.5.25in>mysqladmin -uroot password 123456
D:Program Filesmysql-5.5.25in>mysql -uroot -p123456
mysql> grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option;
mysql> flush privileges;

解释下上面遇到的问题：
1.首先查询有没有开启远程访问（可以让任意IP通过root用户访问）
2.没有开启，则修改host='%'，会报错：ERROR 1062 (23000): Duplicateentry ' %-root'for key'PRIMARY'
3.忽略第二个问题，并flush privileges;（刷新MySQL系统权限相关表，否则会报错：拒绝访问）
4. 通过命令重新登录报错：ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)，原因是密码变成空了，重新设置密码：mysqladmin -uroot password 123456
5.这个时候访问还是报错： host ip is not allowed to connect to this mysql。通过以下两个命令即可解决，
grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option;flush privileges;