在我的情况下，我不能访问mysql，经过3天的研究，我有一个解决方案。这是一个完美的解决方案，因为我已经搜索了/var/run/mysqld/mysqld.我和袜子没有找到文件夹。可以在putty上执行以下命令。

sudo mkdir /var/run/mysqld/
sudo chown -R mysql:mysql /var/log/mysql
sudo mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --socket=/var/run/mysqld/mysqld.sock
sudo /etc/init.d/mysql restart

你会节省宝贵的时间。

This error can also occur if you try to change the directory where the database is stored, but imput the wrong directory in the configuration file (like a typo in the second drive as D instead of the accurate D_). Instead of telling you the typo directory does not exist, it will tell you that you lack permission to access it (leading you to try to change the permissions for the typo directory, which it will let you do). So if you get this error while changing directories, double check the configuration file and make sure you don't have a typo.

升级MySQL为我解决了这个问题。在基于rhel的服务器上，只需运行:

sudo yum upgrade mysql-server

sudo touch /var/lib/mysql/.force_upgrade
sudo rcmysql restart

当我有这个问题的时候

如果您的Linux机器上安装了XAMPP，请尝试将my.cnf文件从/opt/lampp/etc/my.cnf复制到/etc/my.cnf

然后，再次运行mysql -u root…现在您应该有了正确的套接字，并且能够运行MySQL客户端。

您的mysql服务器可能没有运行。输入mysql确保它运行。服务器启动进入终端。