這個問題主要提示是，不能通過'/tmp/mysql.sock'連到服務(wù)器，而php標準配置正是用過'/tmp/mysql.sock'，但是一些mysql安裝方法將mysql.sock放在/var/lib/mysql.sock或者其他的什么地方，你可以通過修改/etc/my.cnf文件來修正它，打開文件，可以看到如下的東東：
[mysqld]
socket=/var/lib/mysql.sock
改一下就好了，但也會引起其他的問題，如mysql程序連不上了，再加一點：
[mysql]
socket=/tmp/mysql.sock
或者還可以通過修改php.ini中的配置來使php用其他的mysql.sock來連，這個大家自己去找找

或者用這樣的方法:
ln -s /var/lib/mysql/mysql.sock /tmp/mysql.sock

還有:
phpmyadmin的說明書有說
The error message "Warning: MySQL Connection Failed: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (111)..." is displayed. What can I do?

For RedHat users, Harald Legner suggests this on the mailing list:

On my RedHat-Box the socket of mysql is /var/lib/mysql/mysql.sock. In your php.ini you will find a line
mysql.default_socket = /tmp/mysql.sock
change it to
mysql.default_socket = /var/lib/mysql/mysql.sock
Then restart apache and it will work.

Here is a fix suggested by Brad Ummer in the phpwizard forum:

First, you need to determine what socket is being used by MySQL.
To do this, telnet to your server and go to the MySQL bin directory. In this directory there should be a file named mysqladmin. Type ./mysqladmin variables, and this should give you a bunch of info about your MySQL server, including the socket (/tmp/mysql.sock, for example).
Then, you need to tell PHP to use this socket.
Assuming you are using PHP 3.0.10 or better, you can specify the socket to use when you open the connection. To do this in phpMyAdmin, you need to complete the socket information in the config.inc.php3.
For example: $cfg['Servers'][$i]['socket'] = '/tmp/mysql.sock';