方法一：采用 SET PASSWORD 命令，确保已经登录MySQL
基本格式 set password for 用户名@localhost = password('password');
set password for root@localhost = password('password');
set password for root@127.0.0.1 = password('password');
set password for root@::1 = password('password');方法二：用 UPDATE 直接编辑 user 表，确保已经登录MySQL
use mysql;
update user set password=password('password') where user='root' and host='localhost';
flush privileges;推荐使用
set password for root@localhost = password('password');
flush privileges;