我刚刚在Mac OS x上安装了MySQL，下一步是设置root用户密码，所以我接下来这样做:
启动终端应用程序以访问Unix命令行。
在Unix提示符下，我执行了以下命令:
cd /usr/local/mysql/bin
./mysqladmin -u root password' password'
但是，当我执行命令时
./mysql -u root，这是答案:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 224
Server version: 5.5.13 MySQL Community Server (GPL)
Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
我不需要密码就能进入mysql命令行!
为什么会这样?
如果您不记得设置的root密码，需要重置密码，请执行以下步骤:
Stop the mysqld server, this varies per install
Run the server in safe mode with privilege bypass
sudo mysqld_safe --skip-grant-tables;
In a new window connect to the database, set a new password and flush the permissions & quit:
mysql -u root
For MySQL older than MySQL 5.7 use:
UPDATE mysql.user SET Password=PASSWORD('your-password') WHERE User='root';
For MySQL 5.7+ use:
USE mysql;
UPDATE mysql.user SET authentication_string=PASSWORD("your-password") WHERE User='root';
Refresh and quit:
FLUSH PRIVILEGES;
\q
Stop the safe mode server and start your regular server back. The new password should work now. It worked like a charm for me :)
Note
运行
更新mysql。SET authentication_string=null WHERE user ='root';
如果您不想为root用户设置密码。或者PASSWORD()函数不适合您。
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';`
