原因：权限的问题
解决办法
grant all privileges on *.* to 'root'@'ip地址' identified by 'mysql 密码';
如果是本地登录：
grant all privileges on *.* to 'root'@'localhost' identified by 'mysql 密码';
开放权限给所有ip设定root登陆：
grant all privileges on *.* to 'root'@'%' identified by 'mysql 密码';
最后：
flush privileges;
