總共有五個會員

$SQLadmin = mysql_query("SELECT * FROM `admin`
");

<form action="admin_update?type=permissions" method="post" id="saveform">
    <table width="300" border="0" cellspacing="10" cellpadding="10" align="center" class="tab">
    <tr>
      <td width="50%">ID</td>
      <td width="50%">Permissions</td>
    </tr>
    <? while ($row = mysql_fetch_array($SQLadmin)){?>
    <tr>
      <td><? echo $row['id'];?></td>
      <td>
        <select name="permissions" class="p100">
        <option value="0" <? if($row['permissions']==0){echo 'selected';}?>>0</option>
        <option value="10" <? if($row['permissions']==10){echo 'selected';}?>>10</option>
        <option value="20" <? if($row['permissions']==20){echo 'selected';}?>>20</option>
        <option value="30" <? if($row['permissions']==30){echo 'selected';}?>>30</option>
        <option value="40" <? if($row['permissions']==40){echo 'selected';}?>>40</option>
        <option value="50" <? if($row['permissions']==50){echo 'selected';}?>>50</option>
        <option value="60" <? if($row['permissions']==60){echo 'selected';}?>>60</option>
        <option value="70" <? if($row['permissions']==70){echo 'selected';}?>>70</option>
        <option value="80" <? if($row['permissions']==80){echo 'selected';}?>>80</option>
        <option value="90" <? if($row['permissions']==90){echo 'selected';}?>>90</option>
        <option value="100" <? if($row['permissions']==100){echo 'selected';}?>>100</option>
      </select>
    </td>
    </tr>
    <? }?>
    <tr>
      <td colspan="2" align="right"><button id="savebtn" class="savebtn" type="submit">Save</button></td>
    </tr>
  </table>
</form>

admin_update

if($type=='permissions')
{
  $permissions = $_POST['permissions'];

  $SQL = mysql_query("UPDATE `admin` SET
    `permissions` = '".$permissions."'
  ");

  echo '成功';
}

共有五個會員，這五個會員都有permissions值
怎樣才可以編輯會員的permissions數據？
每個permissions都是獨立
我這樣寫會沒辦法運作
是哪裡有問題？