ช่วยหน่อยครับระบบจองห้องไม้โชว์วันที่เช่าและวันที่จอง

<?
session_start();
if(empty($user)) 
//if(empty($_SESSION['usermem']))
{
echo "<script language='javascript'>alert('¡ÃسÒà¢éÒÊÙèÃкºÊÁÒªÔ¡¡è͹¤èÐ');</script>";
echo "<meta http-equiv='refresh' content='0;URL=Login.php'>";
}else{
$id_product = $_GET[PrdID];
session_register("sess_idproduct");
session_register("sess_name_prd");
session_register("sess_price");
session_register("sess_num");
$today = date("d-m-Y");  
if (count($sess_idproduct)=="0") {
	$check=1;
} else  if (!in_array($id_product, $sess_idproduct)) {
	$check=1;
}

if ($check==1) {
	include "../config.php";
	$sql="select * from products where id='$id_product' ";
	$result=mysql_db_query($db,$sql);
	$rs=mysql_fetch_array($result);

	$sess_idproduct[]=$rs[productscode];
	$sess_name_prd[]=$rs[productsname];
	$sess_price[]=$rs[productsprice];
	$sess_num[]=0;
}
header("Location: Order.php");
}
?>