สอบถามการ update นอกจากข้อมูลแรก ไม่สามารถแก้ไขข้อมูลอื่นได้เลย

<table width="1202" height="784" border="00" align="center" cellpadding="0" cellspacing="0">
  <tr>
    <td height="10"><form id="form1" name="form1" method="post" action="<? $_SERVER['PHP_SELF']?>">
    <?
	$id= $_GET['id'];
	$sql = "select * from bikeshop where No = '$id';";
	$qry = mysqli_query($con,$sql);
	$result = mysqli_fetch_array ($qry);
?>
   <table width="1201" height="34" border="0">
        <tr>
          <td width="815" align="right"><h4></h4></td>
          <td width="272">admin</td>
            <td width="100" align="right"><h4><a href="../index.php">ออกจากระบบ</a></h4></td>
        </tr>
      </table>
    </form></td>
  
  </tr>
  <tr>
    <td height="218" bgcolor="#FFFFFF"  background="nameshop.jpg"></td>
  </tr>
  <tr>
    <td height="10">&nbsp;</td>
  </tr>
  <tr>
    <td height="479" align="center" valign="top" bgcolor="#D6D6D6"><form id="form2" name="form2" method="post" action="">
      <p>&nbsp;</p>
      <table width="441" height="454" border="1" align="center">
        <tr>
          <td width="104" bgcolor="#C0C0C0">No :</td>
          <td width="327" bgcolor="#C0C0C0"><? echo $result['No']?>&nbsp;</td>
        </tr>
            <tr>
          <td bgcolor="#C0C0C0">ชื่อสินค้า :</td>
          <td bgcolor="#C0C0C0"><input name="name3" type="text" id="name3" value="<? echo $result['Namebike']; ?>" /></td>
        </tr>
        
        <tr>
          <td bgcolor="#C0C0C0">ราคา :</td>
          <td bgcolor="#C0C0C0"><input name="Price" type="text" id="Price" value="<? echo $result['Price']; ?>" /></td>
        </tr>
        <tr>
          <td bgcolor="#C0C0C0">รายละเอียด :</td>
          
          <td bgcolor="#C0C0C0"><input name="Detail" type="text" id="Detail" value="<? echo $result['Detail']; ?>" />          </tr>
        <tr>
          <td bgcolor="#C0C0C0">รูป:</td>
          <td bgcolor="#C0C0C0">&nbsp;
          <input name="Pic" type="text" id="Pic" value="<? echo $result['Pic']; ?>" />
          </td>
        </tr>
        <tr>
          <td bgcolor="#C0C0C0">&nbsp;</td>
          <td bgcolor="#C0C0C0"><input type="submit" name="button3" id="button3" value="ยืนยัน" />
           <input type="submit" name="button4" id="button4" value="ยกเลิก" /></a></td>
        </tr>
      </table>
       <? 
	  if($_POST['button3'])
	  {
$No= $_POST[No] ;
$Namebike= $_POST[name3] ;
$Price = $_POST[Price] ;
$Detail = $_POST[Detail] ;
$Pic = $_POST[Pic] ;

			
 $sql = "UPDATE  `bikeshop` SET  `No` =  '$No',`Namebike` =  '$Namebike',`Price` =  '$Price',`Detail` =  '$Detail',`Pic` =  '$Pic' WHERE CONVERT(  `bikeshop`.`No` USING utf8 ) =  '$id';";

$qry = mysqli_query($con,$sql);
	  echo "<script language='JavaScript'>";
	  echo "alert('ข้อมูลถูกปรับปรุงเรียบร้อยแล้วคะ');";
	  echo"</script>";
	  echo "<script type='text/javascript'> window.location = 'admineditbike.php'</script>";
		  }
		  else if($_POST['button4'])
		  {
			  echo "<script type='text/javascript'> window.location = 'adminindex.php'</script>";
			  }
		  ?>
      <p>&nbsp;</p>
    </form></td>
  </tr>
</table>
<p>&nbsp;</p>
</body>
</html>