Permisi, saya ada permasalahan seputar combobox, dimana data yang ada didalam mysql tidak muncul ketika comboboxnya di klik!
berikut saya sertakan scriptnya, tolong bantuan master2 disini, terimakasih.

<?php
$hostName	= "localhost";
$userName	= "root";
$passWord	= "";
$dataBase	= "db_profil";

mysql_connect($hostName,$userName,$passWord) or die('Koneksi Gagal');
mysql_select_db($dataBase) or die('Database tidak ditemukan');
?>

<tr>
      <td> Prodi </td>
      <td>:</td>
      <td>  
         <select name="prodi">
         	<option value='$p1'>S1 Administrasi Negara</option>
               	<option value='$p2'>D3 administrasi Negara</option>
               	<option value='$p3'>S1 PPKN</option>
               	<option value='$p4'>S1 HUKUM</option>
         <?php
         include "koneksi.php";
            $prodi = $_GET['prodi'];
            $q = mysql_query("select * from tb_profil where prodi ='$_GET [prodi]'"); 
               while ($data = mysql_fetch_array($q)){
                  if ($data[prodi] == 'S1 Admin. Negara'){
            		$p1 = 'selected';
            	}
            	elseif($data[prodi] == 'D3 Admin. Negara'){
            		$p2 = 'selected';
            	}
            	elseif($data[prodi] == 'S1 PPKn'){
            		$p3 = 'selected';
            	}
            	elseif($data[prodi] == 'S1 Ilmu Hukum'){
            		$p4 = 'selected';
               }
            	else{
            		$p1 = '';
            		$p2 = '';
            		$p3 = '';
            		$p4 = '';
            	}
               echo "
               <option value='$p1'>S1 AN</option>
               <option value='$p2'>D3 AN</option>
               <option value='$p3'>S1 PPKN</option>
               <option value='$p4'>S1 HUKUM</option>
               ";
               }
         ?>
         </select></td>
   </tr>

CREATE TABLE IF NOT EXISTS `tb_profil` (
  `email` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  `cpwd` varchar(50) NOT NULL,
  `nim` int(10) NOT NULL default '0',
  `nama` varchar(50) NOT NULL,
  `prodi` enum('s1an','d3an','s1ppkn','s1hukum') NOT NULL,
  `dpa` varchar(50) NOT NULL,
  `alamat` varchar(100) NOT NULL,
  `sex` enum('Laki-Laki','Perempuan') NOT NULL,
  `agama` enum('islam','kristen','katholik','hindu','buddha') NOT NULL,
  `kontak` varchar(20) NOT NULL,
  `tentang` varchar(100) NOT NULL,
  `awalgabung` datetime NOT NULL,
  PRIMARY KEY  (`nim`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;