ListBox ดึงข้อมูลเดิมมาแสดงจากในฐานข้อมูลแล้วมาแก้ไข

<?php
header('Content-type:text/html;charset=UTF-8');
require_once '../inc/connect.inc.php';
$department_id = $_GET[department_id];
$division_id = $_GET[division_id];
$section_id = $_GET[section_id];
if (!isset($_GET['load'])){
			$_GET['load'] = 'department';
}
switch($_GET['load']){
			case 'department':
			$r = mysql_query("SELECT * FROM `department`") or report();  
			echo '<option value="0">-- เลือกฝ่าย --</option>';
			while ($row = mysql_fetch_assoc($r)){
			echo '<option value="',$row['department_id'],'">',
			$row['department_name'],
			'</option>';
} break;
			case 'division':
			$department_id = isset($_GET['department_id'])?intval($_GET['department_id']):0;
			$r = mysql_query("SELECT * FROM `division` WHERE `department_id`=$department_id") or report();  
			echo '<option value="0">-- เลือกแผนก --</option>';
			while ($row = mysql_fetch_assoc($r)){
			echo '<option value="',$row['division_id'],'">',
			$row['division_name'],
			'</option>';
} break;
			case 'section':
			$division_id = isset($_GET['division_id'])?intval($_GET['division_id']):0;
			$r = mysql_query("SELECT * FROM `section` WHERE `division_id`=$division_id") or report();  
			echo '<option value="0">-- เลือกงาน --</option>';
			while ($row = mysql_fetch_assoc($r)){
			echo '<option value="',$row['section_id'],'">',
			$row['section_name'],
			'</option>';
} break;   
}
			function report(){
			return die('<option>'.htmlspecialchars(mysql_error()).'</option>');
}
?>

<tr valign="baseline">
      <td nowrap="nowrap" align="right">อ้างอิงจากฝ่าย:</td>
      <td><select id="department_id" name="department_id" >
        <option value="0">-- เลือก --</option>
      </select></td>
      <td nowrap="nowrap" align="right">&nbsp;</td>
    </tr>
    <tr valign="baseline">
      <td nowrap="nowrap" align="right">อ้างอิงจากแผนก:</td>
      <td><select id="division_id" name="division_id">
        <option value="0">-- เลือก --</option>
      </select></td>