ubuntu20.04 mysql8.0.20 修改root

~#  sudo vi /etc/mysql/mysql.conf.d/mysqld.cnf
----------------------------------------------------------------
skip-grant-tables
-----------------------------------------------------------------

~#  mysql -uroot -p
~# use mysql;
~# flush privileges;
~# ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '你的密码';
~# flush privileges;

备注： 一定要先刷新 flush privileges;