มัน insert ไม่ได้อ่ะ กับ UpDate ไม่ได้อ่ะ SQL อ่ะคับ

<?php 
session_start();
session_register("s_orderid");
include ("connect.php");
$product_id = $_POST ['product_id'];
$amount = $_POST['amount'];




// checknull
function checknull($var,$value)
{
		if (empty($var)){
			echo"<script>
			alert('Pleae Input ".$value."');
			history.back();
			</script>";
		exit();
		}
}
checknull ($product_id,"product_id");
checknull ($amount,"amount");


// SAVE 

$sql="insert into order 
values (' ','$product_id','$amount')";
mysql_query($sql) or die ("SAVE Error!!!");
	include ("connect.php"); 
	$order_id = $_SESSION['s_orderid'];
	$sql="select * from order where order_id = '$order_id'";
	$result = mysql_query($sql) or die ('SQL error');
	$row_user = mysql_fetch_array($result);

echo"<script>
		alert('Number Order : $row[0]');
		alert('Save Data OK');
		window.location='memberhomepage.php';
	</script>";
exit();

?>

<?php 
session_start(); 
include ("connect.php");
$username = trim($_POST['username']); 
$password = trim($_POST['password']);
$repassword = trim($_POST['repassword']);
$name = $_POST ['name'];
$sname = $_POST['sname'];
$address = $_POST['address'];
$tel = $_POST['tel'];
$email = $_POST['email'];



// checknull
function checknull($var,$value)
{
		if (empty($var)){
			echo"<script>
			alert('Please Input ".$value."');
			history.back();
			</script>";
		exit();
		}
}
checknull ($email,"email");
checknull ($username,"username");



	
	
// update
$sql="update profile set  password ='$password',name ='$name', sname = '$sname', address = '$address', tel = '$tel', email = '$email' ";
if (!empty($password))
{
	$sql.="password='$password'";
}
$sql.="where username ='$username'";

mysql_query($sql) or die ("Update Error!!!");
echo"<script>
		alert('Save Data OK');
	</script>";
echo"<center> <a href = 'editprofile.php'>
FORM EDIT </a></center>" ;

?>