MySQL 的 ERROR 1698 (28000): Access denied for user 'root'@'localhost'

1. $ sudo mysql -u root -p
2. $ ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'new-password';
3. $ sudo service mysql stop
$ sudo service mysql start

参考链接：
https://blog.csdn.net/Exception_sir/article/details/82111014
https://blog.csdn.net/jlu16/article/details/82809937
注意第2篇的评论区。