$ export PATH=$PATH:/usr/local/mysql/bin

now,to make this permanent:
$ echo 'export PATH=$PATH:/usr/local/mysql/bin' >> ~/.bash_profile

next, start mysql in safe mode:
$ sudo mysqld_safe --skip-grant-tables;

If this does not work, go to System Preferences and stop MySQL server.
next, On the **other** terminal, you may use the below:

$ mysql -u root

mysql> USE mysql;

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

mysql> FLUSH PRIVILEGES;

mysql> exit;

$ mysql -u root
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH 
caching_sha2_password BY 'yourpassword';

$ mysql -u root -p
Enter password: 
mysql> SELECT user();

next, start the mysql server in normal mode. and you're done with resetting your root password. this worked for mysql 8.0.17 ver. for me.
thanks to everyone on top, https://stackoverflow.com/questions/36099028/error-1064-42000-you-have-an-error-in-your-sql-syntax-want-to-configure-a-pa,

https://www.houseninetytwo.com/how-to-use-mysql-in-terminal-on-mac-os-high-sierra/: ~:文本=你% 5月20日% 20 % 20了% 20,% 2 fmysql % 2 fbin % 2 fmysql。= % 20应该% 20执行% 20 % 20对,返回% 20 % 20版本% % 20 mysql中的20个。

如果你忘记了MySQL的根密码，不记得或者想要闯入.....你可以在Linux或OS X的命令行中重置MySQL数据库密码，只要你知道你所在的机器的root用户密码:

(1)停止MySQL

sudo /usr/local/mysql/support-files/mysql.server stop

(2)安全模式启动:

sudo mysqld_safe --skip-grant-tables

(3)这将是一个持续的命令，直到进程结束，所以打开另一个shell/终端窗口，登录没有密码:

mysql -u root

UPDATE mysql.user SET Password=PASSWORD('password') WHERE User='root';

在上面的UPDATE命令中，只需将'password'替换为您自己的新密码，请确保保留引号

(4)节省和安静

FLUSH PRIVILEGES;

\q

启动MySQL

sudo /usr/local/mysql/support-files/mysql.server start

MySQL 8

关闭MySQL服务器

进入系统首选项-> MySQL 单击停止MySQL服务器按钮

打开两个终端[命令行]窗口 在第一个终端窗口中运行以下命令:

mysqld_safe --skip-grant-tables

在第二个终端窗口中执行以下操作:

4.1. 登录MySQL

mysql -u root

4.2. 在MySQL提示符中执行如下命令:

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

4.3. 退出MySQL

exit;

回到第一个终端窗口并关闭mysqld_safe

5.1. 按CTRL + Z

5.2. 运行以下命令

mysqladmin -u root -p shutdown

5.3. 输入在4.2中设置的新密码。当提示。

启动MySQL服务器[见1.]

之前的评论都没有解决我的Mac上的问题。

我使用下面的命令，它工作。

brew services stop mysql
pkill mysqld
rm -rf /usr/local/var/mysql/ # NOTE: this will delete your existing database!!!
brew postinstall mysql
brew services restart mysql
mysql -u root

mysqld_safe --skip-grant-tables
mysql -u root
UPDATE mysql.user SET authentication_string='yourpasswd' WHERE User='root';
FLUSH PRIVILEGES;
ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'yourpasswd';

每次我的MacBook重启时，我都需要这样做。

停止mysqld服务器。

Mac OS X:系统首选项→MySQL→停止MySQL服务器 Linux(从终端):sudo systemctl停止mysqld.service

Start the server in safe mode with privilege bypass From Terminal: sudo /usr/local/mysql/bin/mysqld_safe --skip-grant-tables In a new terminal window: sudo /usr/local/mysql/bin/mysql -u root This will open the MySQL command-line client. From here enter: UPDATE mysql.user SET authentication_string=PASSWORD('NewPassword') WHERE User='root'; FLUSH PRIVILEGES; quit Stop the mysqld server again and restart it in normal mode. Mac OS X (From Terminal): sudo /usr/local/mysql/support-files/mysql.server restart Linux Terminal: sudo systemctl restart mysqld