如下所示，PHP连接MySQL报错：
SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket 'MySQL' (2)
测试代码如下：
<?php
try
{
$dsn = 'mysql:dbname=php-note;host=localhost;port=3306;charset=utf8';
$username = 'root';
$password = 'root';
new PDO( $dsn, $username, $password);
}
catch (PDOException $e)
{
echo $e->getMessage();
}
【解决方案】
把 host=localhost 改为 host=127.0.0.1 即可！
连接Mysql提示Can’t connect to local MySQL server through socket的解决方法
mysql,Mysqldump,Mysqladmin,php连接mysql服务常会提示下面错误：
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
这是由于修改mysql服务的了socket文件mysql.sock位置，而导致无法通过mysql socket文件连接到mysql服务引起的，具体解决办法如下：
1、查看mysql服务的socket文件位置：
mysql socket文件的位置是在/etc/my.cnf中设置的，cat /etc/my.cnf内容如下：
[mysqld]
datadir=/storage/db/mysql
socket=/storage/db/mysql/mysql.sock
user=mysql
其中socket等于的路径就是socket文件的位置，我们只要修改my.cnf文件,告诉mysql,mysqldump,mysqladmin mysql服务的socket位置在哪里就可以。
2、修改my.cnf文件：
在/etc/my.cnf文件中添加如下内容，并重启mysqls服务，即可解决mysql,mysqldump,mysqladmin的“Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'”问题：
[mysqld]
datadir=/storage/db/mysql
socket=/storage/db/mysql/mysql.sock[mysql]
socket=/storage/db/mysql/mysql.sock[mysqldump]
socket=/storage/db/mysql/mysql.sock[mysqladmin]
socket=/storage/db/mysql/mysql.sock
3、php连接mysql服务提示"Can't connect to local MySQL server through socket..."的解决方法
有时候mysql服务正常运行,用户名密码也完全正确，使用php的mysql_connect函数却连接不了mysql，调用php的mysql_error()函数提示“Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'”，这是我们需要修改/etc/php.ini文件。
在/etc/php.ini文件中"[MySQL]"项下找到"mysql.default_socket"，并设置其值指向正确的mysql服务socket文件即可，如:
[MySQL]
...省略n行...
mysql.default_socket = "/storage/db/mysql/mysql.sock"
4、python连接mysql提示"Can't connect to local MySQL server through socket..."的解决方法:
在连接mysql数据库函数中指定socket文件，如下：
#!/usr/bin/python
from MySQLdb import connect
conn = connect(db="pzy", user="root", host="localhost", unix_socket="/storage/db/mysql/mysql.sock")
cur = conn.cursor()
count=cur.execute("show databases")
print 'there has %s dbs' % count
conn.commit()
conn.close()
5、php pdo连接mysql提示"Can't connect to local MySQL server through socket..."的解决方法:
同样在连接字符串添加mysql socket文件的位置即可，如下:
<?php
$dsn = "mysql:host=localhost;dbname=pzy;unix_socket=/storage/db/mysql/mysql.sock";
$db = new PDO($dsn, 'root', '');
$rs = $db->query("SELECT * FROM qrtest");
while($row = $rs->fetch()){
print_r($row);
}
?>
参考：
http://www.aiezu.com/db/mysql_cant_connect_through_socket.html