引用
http://php.net/manual/en/intro.mssql.php：
The MSSQL extension is not available anymore on Windows with PHP 5.3 or later.
SQLSRV, an alternative driver for MS SQL is available from Microsoft: » 07001.
下载后，请按照此页面上的说明操作：
简而言之：
Put the driver file in your PHP extension directory.
Modify the php.ini file to include the driver. For example:
06000
Restart the Web server.
另请参阅(从该页面复制)
The SQLSRV extension is enabled by adding appropriate DLL file to your PHP extension directory and the corresponding entry to the php.ini file. The SQLSRV download comes with several driver files. Which driver file you use will depend on 3 factors: the PHP version you are using, whether you are using thread-safe or non-thread-safe PHP, and whether your PHP installation was compiled with the VC6 or VC9 compiler. For example, if you are running PHP 5.3, you are using non-thread-safe PHP, and your PHP installation was compiled with the VC9 compiler, you should use the php_sqlsrv_53_nts_vc9.dll file. (You should use a non-thread-safe version compiled with the VC9 compiler if you are using IIS as your web server). If you are running PHP 5.2, you are using thread-safe PHP, and your PHP installation was compiled with the VC6 compiler, you should use the php_sqlsrv_52_ts_vc6.dll file.