mysql -u root -p

GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘%‘ IDENTIFIED BY ‘password‘ WITH GRANT OPTION;

如果你想允许用户root从ip为192.168.1.123的主机连接到mysql服务器，并使用root作为密码   
使用mysql库：use mysql
查询信息：select user,host from user
update user set host="%" where user="root"
GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘192.168.1.123‘IDENTIFIED BY ‘password‘ WITH GRANT OPTION;   

flush privileges;

firewall-cmd --zone=public --add-port=3306/tcp --permanent

firewall-cmd --reload

firewall-cmd --list-ports