这就是对我有效的方法:

Make sure no other MySQL process is running. To check this do the following: From the terminal, run this command: lsof -i:3306 If any PID is returned, kill it using kill -9 PID Go to System Preferences → MySQL → check if any MySQL instances are running, stop them. Start MySQL with the command: sudo /usr/local/mysql/bin/mysqld_safe --skip-grant-tables The password for every user is stored in the mysql.user table under columns User and authentication_string respectively. We can update the table as: UPDATE mysql.user SET authentication_string='your_password' where User='root'

停止MySQL服务器

sudo /usr/local/mysql/support-files / mysql。服务器停止

以安全模式启动MySQL

Sudo /usr/local/mysql/bin/mysqld_safe——skip-grant-tables &

修改root用户密码

/usr/local/mysql/bin/mysql -u root

use mysql;
UPDATE user SET authentication_string=PASSWORD('NEW_PASSWORD') WHERE user='root';
FLUSH PRIVILEGES;
exit

测试

执行/usr/local/mysql/bin/mysql -u root命令

现在输入新密码开始使用MySQL。

当您登录MySQL终端时，请尝试执行FLUSH PRIVILEGES命令。如果这不起作用，请在MySQL终端中尝试以下命令集

mysql -u root

mysql> USE mysql;
mysql> UPDATE user SET password=PASSWORD("NEWPASSWORD") WHERE User='root';
mysql> FLUSH PRIVILEGES;
mysql> quit

用你想要的任何密码更改NEWPASSWORD。应该都准备好了!

更新:从MySQL 5.7开始，密码字段被重命名为authentication_string。修改密码时，使用以下查询来修改密码。所有其他命令保持不变:

mysql> UPDATE user SET authentication_string=PASSWORD("NEWPASSWORD") WHERE User='root';

请不要使用MySQL 8.0+

mysql> UPDATE mysql.user SET authentication_string='password' WHERE User='root'; 

因为它覆盖了authentication_string，它应该是一个哈希而不是纯文本，而是使用:

mysql> `ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';` 

我认为这是可行的:

ALTER USER 'root'@'localhost' IDENTIFIED BY 'YOURNEWPASSWORD'

(注意，如果你的用户名不是root，你可能应该用你的用户名替换root。)

要引用MySQL 8.0.15 +， password()函数不可用。使用下面的命令。

请使用

UPDATE mysql.user SET authentication_string='password' WHERE User='root';

mysql网站上提供的说明非常清楚，比上面提到的还要清楚

$ sudo /usr/local/mysql/support-files/mysql服务器停止 $ sudo /usr/local/mysql/support-files/mysql服务器启动——skip-grant-tables /usr/local/mysql/bin/mysql mysql> FLUSH PRIVILEGES; mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass'; mysql>退出或按Ctrl + z $ sudo /usr/local/mysql/support-files/mysql服务器停止 $ sudo /usr/local/mysql/support-files/mysql服务器启动 /usr/local/mysql/support-files/mysql -u root -p 输入新密码，即MyNewPass

参考:http://dev.mysql.com/doc/refman/5.7/en/resetting-permissions.html