ข้อมูลซ้ำกัน ใน list menu ต้อง เขียนโค้ดยังไงบ้างคับ

<?
$sql="select d.detail_id,d.supplier_id,d.code,d.description,d.s_n,d.buy_date,d.s_warranty,d.s_out_warranty,d.s_price,d.s_unit,d.s_total,d.customer, d.sell_date,d.c_warranty,d.c_out_warranty,d.c_price,d.c_unit,d.c_total,s.supplier_id,s.supplier_name
			  		from tbl_detail AS d
			  		JOIN tbl_supplier AS s ON d.supplier_id = s.supplier_id
			  		WHERE detail_id='$_GET[detail_id]' "; 
		$result=mysql_query($sql);
		$rs=mysql_fetch_array($result);
		?>

<select name="ddlSupplierID" class="txtbox" id="ddlSupplierID">
         <option value="<?php echo $rs["supplier_id"]?>"><?php echo $rs["supplier_name"]?></option>
         <?
$sql_group = "select * from tbl_supplier order by supplier_id asc";
$dbquery_group = mysql_query($sql_group);
$num_rows_group = mysql_num_rows($dbquery_group);
while ($result = mysql_fetch_array($dbquery_group))
{
if($_POST["supplier_id"] == $result["supplier_id"])
{
$sel="selected";
}
else
{
$sel="";
}
?>
         <option value="<?=$result["supplier_id"];?>" <?=$sel;?>>
           <?=$result["supplier_name"];?>
           </option>
         <?
}
?>
       </select>