มันเออเรอแบบนี้ต้องแก้ยังไงค่ะ รบกวนช่วยหน่อยนะค่ะ

<?
session_start();
?>
<?
include "connect.php";
$name = $_POST["name"];
$email = $_POST["email"];
$phone = $_POST["phone"];
$address = $_POST["address"];
$total = $_POST["total_order"];
if ($name == ""){
	echo "<script> alert('กรุณากรอกชือ-สกุล')</script>";
	echo "<script>history.back();</script>"; 
exit();
} else if ($email == "") {
	echo "<script> alert('กรุณากรอกอีเมล์')</script>";
	echo "<script>history.back();</script>";
	exit();
} else if ($phone== ""){
	echo "<script> alert('กรุณาเบอร์โทรศัพท์')</script>";
	echo "<script>history.back();</script>";
exit();
} else if ($address == "") {
echo "<script> alert('กรุณากรอกที่อยู่')</script>";
	echo "<script>history.back();</script>"; 
exit();
} 
$date_now = date("Y-m-d");
$sql1= 'insert into tb_orders '.
                        '( order_name , order_address , order_email , order_phone , order_total , order_date )'.
           " values ( '$name', '$address', '$email', '$phone', '$total', '$date_now')";  

mysql_query($sql1);
$order_id=mysql_insert_id(); 
 
for($i=0; $i<count($sess_id); $i++) {

     $sql3 = 'insert into tb_orders_detail(order_id, product_id, order_number)'.
                 " values ('$order_id' , '$sess_id[$i]','$sess_num[$i]')" ;
     mysql_query($sql3);
}
session_unregister("sess_id");
session_unregister("sess_name");
session_unregister("sess_price");
session_unregister("sess_num");
mysql_close();

header("location:finish_order.php?order_id=".$order_id);
?>