ค้นหาแบบ dropdown

ข้อมูลไม่ขึ้นค่ะ ช่วยดูโค้ดให้หน่อยค่ะ 

ค้นหา :<select name="Search1">
<option value="n_credit" <? if($Search1=="n_credit"){ ?>selected<? }?>>ประเภทสินเชื่อ</option>
<option value="id_credit" <? if($Search1=="id_credit"){ ?>selected<? }?>>เลขที่บัญชี</option>
<option value="name" <? if($Search1=="name"){ ?>selected<? }?>>ชื่อ</option>
<option value="lastname" <? if($Search1=="lastname"){ ?>selected<? }?>>นามสกุล</option>
<option value="idcard" <? if($Search1=="idcard"){ ?>selected<? }?>>เลขบัตรประชาชน</option>

</select>
<input name="Search"  type="text" size="20" value="<? echo $Search?>"onFocus="this.value = '';">
<input type="submit" name="submit" value="Search">
<?
if(!isset($start)){
$start = 0;
$page=1;
}
$limit = '10';

if($strSearch=="Y"){
$Qtotal = mysql_query("select * from customer Where ".$Search1." like '%".$Search."%' group by id_credit  ");
}else{
$Qtotal = mysql_query("select * from customer group by id_credit");
}

$total = mysql_num_rows($Qtotal); 
if($strSearch=="Y"){
$Query = mysql_query("select * from customer Where ".$Search1." like '%".$Search."%' group by id_credit order  by  id_credit DESC LIMIT $start,$limit");
}else{
$Query= mysql_query("select * from customer group by id_credit order  by  id_credit DESC LIMIT $start,$limit");
}
?><br>
<table width="822" height="54" border="0">
  <tr align="center" valign="middle" bgcolor="#333333">
    <td width="146" bgcolor="#696969"><font color="#FFFFFF">ประเภทสินเชื่อ</font></td>
    <td width="143" bgcolor="#696969"><font color="#FFFFFF">เลขที่บัญชี</font></td>
    <td bgcolor="#696969"><font color="#FFFFFF">คำนำหน้าชื่อ</font></td>
    <td bgcolor="#696969"><font color="#FFFFFF">ชื่อ</font></td>
    <td bgcolor="#696969"><font color="#FFFFFF">นามสกุล</font></td>
    <td bgcolor="#696969"><font color="#FFFFFF">แก้ไข</font></td> </tr>
    <td align="center" valign="middle"><? echo $n_credit  ?></td>
    <td align="center" valign="middle"><? echo $arr['id_credit'] ?></td>
    <td width="90" align="center" valign="middle"><? echo $arr['titlename'] ?></td>
    <td width="183" align="center" valign="middle"><? echo $arr['name'] ?></td>
    <td width="166" align="center" valign="middle"><? echo $arr['lastname'] ?></td>
    <td width="36" align="center" valign="middle">&nbsp;</td>
  </tr>
</table>