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。
一旦你安装了MySQL，你需要建立“根”密码。如果您没有设置根密码，那么就没有根密码，您也不需要密码来登录。
因此，话虽如此，您需要建立一个根密码。
使用终端输入如下:
安装:设置root用户密码:
/usr/local/mysql/bin/mysqladmin -u root password NEW_PASSWORD_HERE
如果你犯了一个错误，或者需要修改root密码，请使用以下方法:
修改root密码:
cd /usr/local/mysql/bin/
./mysql -u root -p
> Enter password: [type old password invisibly]
use mysql;
update user set password=PASSWORD("NEW_PASSWORD_HERE") where User='root';
flush privileges;
quit
macOS v10.14 (Mojave)及更高版本，从Mac OS X DMG安装程序安装5.7.26。
当尝试使用其他用户发布的UPDATE命令时，会导致以下错误:
错误1820 (HY000):在执行此语句之前，您必须使用ALTER USER语句重置密码。
复制安装程序提供给您的密码，打开终端，然后执行以下操作:
mysql -uroot -p
ALTER USER 'root'@'localhost' IDENTIFIED BY 'YOURPASSWORDHERE';
