Mysql5+处理办法：
mysql -hlocalhost -uroot -p
grant all privileges on *.* to root@"%" identified by ".";
flush privileges;
Mysql8+处理办法：
mysql -hlocalhost -uroot -p
grant all privileges on *.* to 'root'@'%' with grant option;
flush privileges;
如果没有'root'@'%' 用户。mysql安装的时候默认的root是root@localhost
所以授权之前还得新建一个用户。
mysql >create user 'root'@'%' identified by 'root';
