Check box

<h2> Form Study </h2>
<form  method="post">
Hobbies:<input type="checkbox" name="hobbies[]" value="reading">Reading<br>
             <input type="checkbox" name="hobbies[]" value="talking">Talking<br>
             <input type="checkbox" name="hobbies[]" value="eating">Eating<br>
             <input type="checkbox" name="hobbies[]" value="singing">Singing<br>
<input type="submit" name="sub" value="save">
</form>
<?php
if(isset($_POST['sub']))
{
$nhobbies=$_POST['hobbies'];
$nselected_hobbies= "";
foreach($nhobbies as $nhobbie)
{
$nselected_hobbies .= $nhobbie . ", ";
}
$nselected_hobbies = substr($nselected_hobbies, 0, -3);
$sql = mysql_query("insert into form values('$nselected_hobbies')");

}
?>