在我把事情搞砸了之前，当我用$ mysql -u root -p登录时，显示数据库：
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| game_data |
| test |
+--------------------+
然后我试图创建一个新的用户，发现PRIVILEGES有问题。
我现在如何修复MySQL？
我找不到数据库'mysql'，无法创建数据库，无法创建用户，任何尝试做的事情都会得到一个错误。用户'root’@‘localhost’(使用密码：YES)被拒绝访问。
我应该用MacPorts重新安装MySQL吗？如果重新安装，我将失去数据库$ mysql -u root -p，对吗？
1.按照以下步骤操作。用--skip-grant-tables选项（安全设置）启动MySQL服务器实例或守护进程。执行这些语句。
如果遇到上述未知字段密码错误，请使用：
update user set authentication_string=password('my_password') where user='root';
--skip-grant-tables选项的情况下重启实例/daemon。$ mysql -u root -p
输入密码：my_password
sudo mv /usr/local/mysql/data/ibdata1 /usr/local/mysql/data/ibdata1.bak
sudo mv /usr/local/mysql/data/ib_logfile0 /usr/local/mysql/data/ib_logfile0.bak
sudo mv /usr/local/mysql/data/ib_logfile1 /usr/local/mysql/data/ib_logfile1.bak
sudo cp -a /usr/local/mysql/data/ibdata1.bak /usr/local/mysql/data/ibdata1
sudo cp -a /usr/local/mysql/data/ib_logfile0.bak /usr/local/mysql/data/ib_logfile0
sudo cp -a /usr/local/mysql/data/ib_logfile1.bak /usr/local/mysql/data/ib_logfile1
sudo /etc/init.d/mysql restart
以上这些对我来说都没有帮助。我发现我需要清除插件方法。在5.6中，我可以做到：
sudo mysql -u root
use mysql;
[mysql] update user set plugin='' where User='root';
[mysql] flush privileges;
在5.7中，我发现我需要：
sudo mysql -u root
use mysql;
[mysql] update user set plugin='mysql_native_password' where User='root';
[mysql] flush privileges;
根据文档，如果插件设置为空字符串，它应该有效地默认为mysql/native/password，但可能会被空的password hash混淆。更多的细微差别，你可以阅读这里的文档。 https://dev.mysql.com/doc/refman/5.7/en/native-authentication-plugin.html
另外，要确保在表user中需要的记录有空的plugin字段（可以有，例如，"unix_socket"）。
自从5.5.7版本的mysql有各种 auth插件支持 https://dev.mysql.com/doc/refman/5.6/en/authentication-plugins.html
所以如果你有非空的plugin字段，那么密码会被忽略，并且在mysql错误日志中会有警告（对我来说是/var/log/mysql/error.log）：
[Warning] 'user' entry 'root@localhost' has both a password and an authentication plugin specified. The password will be ignored.
grep 'temporary password' /var/log/mysqld.log
Sort date (newest date)
你可能会看到这样的东西；
[root@SERVER ~]# grep 'temporary password' /var/log/mysqld.log
2016-01-16T18:07:29.688164Z 1 [Note] A temporary password is generated for root@localhost: O,k5.marHfFu
2016-01-22T13:14:17.974391Z 1 [Note] A temporary password is generated for root@localhost: b5nvIu!jh6ql
2016-01-22T15:35:48.496812Z 1 [Note] A temporary password is generated for root@localhost: (B*=T!uWJ7ws
2016-01-22T15:52:21.088610Z 1 [Note] A temporary password is generated for root@localhost: %tJXK7sytMJV
2016-01-22T16:24:41.384205Z 1 [Note] A temporary password is generated for root@localhost: lslQDvgwr3/S
2016-01-22T22:11:24.772275Z 1 [Note] A temporary password is generated for root@localhost: S4u+J,Rce_0t
[root@SERVER ~]# mysql_secure_installation
Enter password for user root:
The existing password for the user account root has expired. Please set a new password.
New password:
Re-enter new password:
如果你看到它写着
... Failed! Error: Your password does not satisfy the current policy requirements
That means your password needs to have a character such as ! . # - etc...
mix characters well, upper case, lower case, ! . , # etc...
New password:
Re-enter new password:
The 'validate_password' plugin is installed on the server.
The subsequent steps will run with the existing configuration
of the plugin.
Using existing password for root.
Estimated strength of the password: 100
Change the password for root ? ((Press y|Y for Yes, any other key for No) : Y
New password:
Re-enter new password:
Estimated strength of the password: 100
Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : Y
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.
Remove anonymous users? (Press y|Y for Yes, any other key for No) : Y
Success.
Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.
Disallow root login remotely? (Press y|Y for Yes, any other key for No) : Y
Success.
By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.
Remove test database and access to it? (Press y|Y for Yes, any other key for No) : Y
- Dropping test database...
Success.
- Removing privileges on test database...
Success.
Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.
Reload privilege tables now? (Press y|Y for Yes, any other key for No) : Y
Success.
All done!
[root@SERVER ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 5.7.10 MySQL Community Server (GPL)
&001
如果你看到它写着
&001
&001
(https://www.youtube.com/watch?v=L2m3BM28Mz0)，看最后10分钟的[这个视频]&003，它教你如何做。
试试：
mysql --no-defaults --force --user=root --host=localhost --database=mysql
UPDATE user SET Password=PASSWORD('NEWPASSWORD') where USER='root';
FLUSH PRIVILEGES;