<?php
ob_start();
$id = (int) $_GET['id'];
$location = 'Location: download.php';
if($id > 0)
{	
	mysql_connect('localhost','username','password');
	mysql_select_db('db');
	$output = mysql_fetch_assoc(mysql_query("SELECT downloads, link FROM download WHERE id='$id'"));
	if(file_exists($output['link']))
	{
		$downloads = $output['downloads'] + 1;
		mysql_query("UPDATE download SET downloads = '$downloads' WHERE id = '$id'");
		$location = 'Location: '.$output['link'];
	}
}
header($location);
ob_end_clean();
exit();
?>