重置或修改密码请输入sudo dpkg-reconfigure mysql-server-X。X (X.X是mysql版本你已经安装，即5.6,5.7)，然后你会提示一个屏幕，你必须设置新密码，然后在下一步确认密码，只是等待一会儿。就是这样。

该任务指导用户在Ubuntu操作系统下设置/修改/重置MySQL root密码。在终端中输入以下行。

停止MySQL服务器:sudo /etc/init.d / mysql停止 (在某些情况下，如果/var/run/mysqld不存在，你必须首先创建它:sudo mkdir -v /var/run/mysqld && sudo chown mysql /var/run/mysqld 启动mysqld配置:sudo mysqld——skip-grant-tables & 以root身份登录MySQL: MySQL -u root MySQL 用你的新密码替换YOURNEWPASSWORD:

MySQL < 8.0

UPDATE mysql.user SET Password = PASSWORD('YOURNEWPASSWORD') WHERE User = 'root';
FLUSH PRIVILEGES;

如果你的MySQL使用新的认证插件，你将需要使用:update user set plugin="mysql_native_password" where user ='root';在冲洗特权之前。

注意:在某些版本，如果密码列不存在，你可能想尝试: UPDATE user SET authentication_string=password('YOURNEWPASSWORD') WHERE user='root';

注意:这种方法不是最安全的重置密码的方法，但它是有效的。

对于MySQL >= 8.0

FLUSH PRIVILEGES;
ALTER USER 'root'@'localhost' IDENTIFIED BY 'YOURNEWPASSWORD';
FLUSH PRIVILEGES;

最后一步:

正如@lambart的评论中所提到的，你可能需要杀死你启动的临时无密码mysql进程，即sudo killall -9 mysqld，然后启动正常的守护进程:sudo service mysql start

引用:

该任务指导用户在Ubuntu Linux下设置/修改/重置MySQL root密码 如何重置Root用户密码(v5.6) 如何重置Root用户密码(v8.0)

这就是我的解决方案。我在Ubuntu 18.04工作: https://stackoverflow.com/a/46076838/2400373

但是重要的是最后一步的改变:

UPDATE mysql.user SET authentication_string=PASSWORD('YOURNEWPASSWORD'), plugin='mysql_native_password' WHERE User='root' AND Host='localhost'; 

正如mysql文档中password()函数所说:

此函数在MySQL 8.0.11中被移除。

这将使mysql v8.0.11及更新版本的所有现有答案都失效。

根据mysql文档，重置root密码的新通用方法如下:

The preceding sections provide password-resetting instructions specifically for Windows and Unix and Unix-like systems. Alternatively, on any platform, you can reset the password using the mysql client (but this approach is less secure): Stop the MySQL server if necessary, then restart it with the --skip-grant-tables option. This enables anyone to connect without a password and with all privileges, and disables account-management statements such as ALTER USER and SET PASSWORD. Because this is insecure, if the server is started with the --skip-grant-tables option, it enables --skip-networking automatically to prevent remote connections. Connect to the MySQL server using the mysql client; no password is necessary because the server was started with --skip-grant-tables: shell> mysql In the mysql client, tell the server to reload the grant tables so that account-management statements work: mysql> FLUSH PRIVILEGES; Then change the 'root'@'localhost' account password. Replace the password with the password that you want to use. To change the password for a root account with a different host name part, modify the instructions to use that host name. mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass'; You should now be able to connect to the MySQL server as root using the new password. Stop the server and restart it normally (without the --skip-grant-tables and --skip-networking options).

回应rogerdpack的评论:如果你不知道MySQL的根密码，并且你不关心MySQL的数据/设置，你可以重新安装它并重置根密码，如下所示:

sudo apt-get remove --purge mysql-server mysql-client mysql-common
sudo rm -rf /var/lib/mysql
sudo apt-get install -y mysql-server mysql-client 

安装过程中，您可以选择root用户的密码:

你可以尝试以下步骤来重置mysql的root密码:

首先停止Mysql服务

sudo /etc/init.d/mysql stop 

以root用户登录，不需要密码 Sudo mysqld_safe—skip-grant-tables &

登录mysql终端后，你需要执行更多的命令:

use mysql;




UPDATE mysql.user SET authentication_string=PASSWORD('solutionclub3@*^G'), plugin='mysql_native_password' WHERE User='root';


flush privileges;


sudo mysqladmin -S /var/run/mysqld/mysqld.sock shutdown

重启mysql服务器后 如果你仍然面临错误，你必须访问: 重置MySQL的root密码