anti SQL injectiont pada php

/* created script by Last Qye */
if (strpos($_SERVER['REQUEST_URI'], "select") || 
strpos($_SERVER['REQUEST_URI'], "concat") || 
strpos($_SERVER['REQUEST_URI'], "union") || 
strpos($_SERVER['REQUEST_URI'], "base64"))

{
echo "

404 Not Found!

";
@header("HTTP/1.1 414 Request-URI Too Long");
@header("Status: 414 Request-URI Too Long");
@header("Connection: Close");
@exit;
}
/* created script by Last Qye */