1.修改配置文件

sudo vim /etc/mysql/my.cnf
把bind-address参数的值改成你的内/外网IP或0.0.0.0,或者直接注释掉这行.

2.登录数据库
mysql -u root -p

输入密码
mysql> use mysql;

3.查询host
mysql> select user,host from user;

4.创建host
如果没有"%"这个host值,就执行下面这两句:
mysql> update user set host='%' where user='root';
mysql> flush privileges;

5.6版本：
update mysql.user set password=PASSWORD('root') where User='root';
flush privileges;

5.授权用户
任意主机以用户root和密码mypwd连接到mysql服务器
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'mypwd' WITH GRANT OPTION;
mysql> flush privileges;

IP为192.168.1.102的主机以用户myuser和密码mypwd连接到mysql服务器
mysql> GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'192.168.1.102' IDENTIFIED BY 'mypwd' WITH GRANT OPTION; 
mysql> flush privileges;

PS：以上为授权方法，以下为改表方法：

mysql> use mysql;
mysql> update user set host='%' where user='root';
mysql> flush privileges;