อัพเดทข้อมูล แต่มันนไม่ยอมอัพเดท ตามเงื่อนไขนะครับ

<form name="form1" method="post" action="addsale.php">
    <label>
      <input type="text" name="sale" id="sale">
    </label>
    <input type="text" name="step" id="step">
    <label>
      <input type="submit" name="button" id="button" value="Submit">
    </label>
  </form></TD>

<?
session_start();
$id_new=$_GET[id_new];
?>
<?php
include "connect.php";
$objDB = mysql_select_db("leasing");
$strSQL="select * from leasing  where id_new='$id_new' ";
mysql_query("SET NAMES tis620");
$strSQL = "UPDATE leasing SET ";
$strSQL .="sale = '".$_POST["sale"]."' ";
$strSQL .=",step = '".$_POST["step"]."' ";
$strSQL .="WHERE id_new = '$id_new' ";
$objQuery = mysql_query($strSQL);
if($objQuery)
{
	echo "Save Done.";
}
else
{
	echo "Error Save [".$strSQL."]";
}