Ubuntu下MySQL???????????????

Ubuntu下MySQL???????????????

我是ubuntu用户,安装MySQL出错
koskers@KOSKERS:~$ mysql
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
koskers@KOSKERS:~$
不能运行,急啊急啊急啊急啊急啊急啊急啊急啊急啊急啊急啊急啊急啊急啊!
$mysql -h hostname -u username -p
hostname----数据库服务器的主机名