ช่วยหน่อยคะ SELECT ซ้อน SELECT PHP &SQL มีCODE ให้ดูคะ

<center><form action=''  method='get'>
เลือกประเภทสินค้า : 
<select name='seltype'>
<option value='CD'>CD</option>
<option value='DVD'>DVD</option>
<option value='CD+DVD'>CD+DVD</option>
<option value='Concert'>Concert</option>
</select>ศิลปิน<label>
<select name='selArtist'>
  <option value='GD-TOP'>GD-TOP</option>
  <option value='B2ST/BEAST'>B2ST/BEAST</option>
  <option value='4minute'>4minute</option>
  <option value='MBLAQ'>MBLAQ</option>
  <option value='SISTAR'>SISTAR</option>
  <option value='Orange Caramel'>Orange Caramel</option>
  <option value='KARA'>KARA</option>
  <option value='Secret'>Secret</option>
  <option value='SNSD'>SNSD</option>
  <option value='Coed School'>Coed School</option>
  <option value='SHINee'>SHINee</option>
  <option value='Seungri (Big Bang)'>Seungri (Big Bang)</option>
  <option value='After School'>After School</option>
  <option value='IU'>IU</option>
  <option value='FTIsland'>FTIsland</option>
  <option value='T-ARA'>T-ARA</option>
  <option value='Super Junior'>Super Junior</option>  
  </select><input type="submit"value="แสดง"/></label>
</form></center>

<?php
$h='localhost';$u='root'; $p='root'; 
mysql_connect($h,$u,$p); //1 connect
mysql_select_db('test'); //2 slect database
mysql_query('set names utf8'); //แก้ปัญาหาการไม่โชว์ภาษาไทย ให้โชว์
// $sql="SELECT * FROM product WHERE type  and Artist='".$_GET['seltype']." and ".$_GET['selArtist']"order by type";  
$sql="SELECT * FROM product WHERE type='".$_GET['seltype']."'order by type"; // 3 build SQL command ถ้าจะให้แสดงทั้งหมดไใ่ต้องใส่ where,,select * = เลือกฟิลด์ทั้งหมด
$sql="SELECT * FROM product WHERE Artist='".$_GET['selArtist']."'order by type";;  
$result = mysql_query($sql); //4 query a record
echo "<left><table border=0px>";
while ($row = mysql_fetch_array($result) ){   //คืนค่าเรคคอร์ด
echo "<tr>";
echo "<td><img src='pic product/" .$row['picture']."'width=140px height=140px></td>";
echo "<td>".'<b>'.$row['thai_name'].'</b>'.'<br>'."รหัสสินค้า: ".$row['code'].'<br>'."ประเภท: ".$row['type'].
'<br>'."รายละเอียด: ".$row['detail'].'<br>'."ราคา: ".$row['price']." บาท"."</td>";
echo "</tr>";
}
echo "</table></left>";
?>