ช่วยหน่อยครับ ที่เมื่อเราจะแก้ไขข้อมูล dropdownlist ให้แสดงค่าด้วยก่อนแก้ไข(จากฐานข้อมูล)

<?php
$select_id = 3;

$query = mysql_query("SELECT * FROM group ORDER BY ID ASC");

while ($row = mysql_fetch_array($query))
{
if($select_id == $row['ID']){
$options .= '<option value="'.$row["ID"].'" selected="selected">'.$row['ur_field'].'</option>';
}else{
$options .= '<option value="'.$row["ID"].'">'.$row['ur_field'].'</option>';
}
}//while

echo '<select>'.
      $options.
      '</select>'
;

<?

$sqlunit = "SELECT * From tbunits ORDER BY name_units ASC ";
$rsunit = mysql_query($sqlunit);
?>
                <td width="300" align="right" valign="middle"><span class="style29">หน่วยงาน :</span></td>
                <td width="300" align="left" valign="middle">&nbsp;<select name="dllunit" size="1" id="select">
	<?
	while($rwunit = mysql_fetch_array($rsunit))
	{
		$id_unit=$rwunit["id_units"];
		$name_unit=$rwunit["name_units"];
		if($id_unit==$objResult["id_units"])
		{
		  $sel = "selected";
		}
		else
		{
		  $sel = "";
		}
	?>
	<option value="<?=$id_unit;?>" <?=$sel;?>><?=$name_unit;?></option>
	<?
	}
	?>
</select>

<?

$sqlunit = "SELECT * From tbunits ORDER BY name_units ASC ";
$rsunit = mysql_query($sqlunit);
?>
                <td width="300" align="right" valign="middle"><span class="style29">หน่วยงาน :</span></td>
                <td width="300" align="left" valign="middle">&nbsp;<select name="dllunit" size="1" id="select">
	<?

	
	while($rwunit = mysql_fetch_array($rsunit))
	{
		$id_unit=$rwunit["id_units"];
		$name_unit=$rwunit["name_units"];
		if($id_unit==$objResult["id_units"])
		{
		  $sel = "selected";
		}
		else
		{
		  $sel = "";
		}
	?>
	<option value="<?=$id_unit;?>" <?=$sel;?>><?=$name_unit;?></option>
	<?
	}
	?>
</select>