Simple Search Form - PHP MYSQL

<?php
    // koneksi.php
$cn = mysql_connect("host","root","");
mysql_select_db("db",$cn);
?>

<?php // form_search.php ?>
<form action="url" method="post">
<input type="text" name="q" id="q"/>
<input type="submit" name="cari" id="cari" value="cari"/>
</form>

<?php
    // search.php
    include "koneksi.php";
    include "form_search.php";

    $q=mysql_query("SELECT * FROM mytable WHERE myfield LIKE '%".$_POST["q"]."%'");
    while($r=mysql_fetch_array($q)){
    echo $r["myfield"];
    // or
    echo $r[1].$r[2].$r[3];
    }
?>