要更新“root”Mysql用户密码，你必须记住，你将需要超级用户权限。如果您拥有超级用户权限，请尝试执行以下命令:

MySQL 5.7.6及以上版本

sudo su
service mysql stop
mysql -u root
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
\q;
exit
mysql -u root -p MyNewPass

MySQL 5.7.5及更早版本

sudo su
service mysql stop
mysql -u root
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('MyNewPass');
\q;
exit
mysql -u root -p MyNewPass

官方和简单的方法来重置根密码在ubuntu服务器…

如果你在16.04 14.04 12.04

sudo dpkg-reconfigure mysql-server-5.5

如果你在10.04:

sudo dpkg-reconfigure mysql-server-5.1

如果您不确定安装了哪个mysql-server版本，您可以尝试:

dpkg --get-selections | grep mysql-server

mysql-server-5.7的更新说明

请注意，如果您使用的是mysql-server-5.7，则不能使用上面所示的更简单的dpkg-reconfigure方法。

如果你知道密码，登录并运行这个:

UPDATE mysql.user SET authentication_string=PASSWORD('my-new-password') WHERE USER='root';
FLUSH PRIVILEGES;

或者，您可以使用以下方法:

sudo mysql_secure_installation

这将询问您一系列关于保护安装的问题(强烈推荐)，包括是否需要提供新的根密码。

如果你不知道root密码，请参考这个以ubuntu为中心的进程写上去。

查看更多信息:

https://help.ubuntu.com/16.04/serverguide/mysql.html https://help.ubuntu.com/14.04/serverguide/mysql.html

当更改/重置MySQL密码时，上面列出的以下命令没有帮助。我发现进入终端并使用这些命令是毫无意义的。相反，使用命令sudo停止一切。如果有帮助的话，删除windows的system32。

设置MySQL密码

停止MySQL数据库服务

sudo /etc/init.d/mysql stop

创建一个新的mysqld目录

Sudo mkdir /var/run/mysqld/

给予mysql用户访问权限

Sudo chown mysql /var/run/mysqld/

以安全模式启动MySQL…

Sudo mysqld_safe—skip-grant-tables &

无需密码登录数据库服务器

Sudo mysql -u root

使用默认的mysql数据库

使用mysql;

修改root密码

update user set authentication_string=PASSWORD(" new_passwor_here ") where user ='root';

保存更改 冲洗特权; 退出; 停止MySQL安全模式，启动MySQL默认服务

sudo /etc/init.d/mysql stop

sudo /etc/init.d/mysql start

使用root新密码重新登录MySQL数据库

-u root -p

***来源:https://websiteforstudents.com/resetting-mysql-root-password-on-ubuntu-16-04-17-10-and-18-04-lts/

我还没有看到MySQL 8.0指南中推荐的官方步骤，这是唯一适合我的步骤。下面是这些步骤的总结。

Stop the MySQL server if it is running. Look in /var/lib/mysql/, /var/run/mysqld/, or /usr/local/mysql/data/ to find the pid file with the server's process ID. Generally the file begins with either mysqld or your system's host name and ends with .pid. Replace mysql-data-directory and host_name that you just found, in the following command: $ sudo kill `sudo cat /mysql-data-directory/host_name.pid` This command will create a text file in /tmp/mysql-init with the SQL statement and makes the mysql user the owner. Replace in the command MyNewPass with your own password. $ echo "ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';" > /tmp/mysql-init && sudo chown mysql /tmp/mysql-init Start the MySQL server by running the following command on the command line. After this the password is updated and you can close the server again with CTRL+C. $ sudo mysqld --user=mysql --init-file=/tmp/mysql-init & Remove the temporary file with your password: $ sudo rm /tmp/mysql-init

Instead of resetting the password there is a work around on the local machine if you have setup phpmyadmin to connect without giving the password or username. Check this out by starting mysql, apache etc. I have xampp installed in my local machine. So starting the xampp will start all the necessary services. Now going to http://localhost/phpmyadmin shows me all the databases. This confirms that you have saved the username and passsword in the config file of phpmyadmin which can be found in the phpmyadmin install location. If you have xampp installed the phpmyadmin folder can be found in the root folder of xampp installation. Search for the word password in the config.inc.php file. There you will find the password and username.