Trying to call session variables to display

Hi there,
To put it simple, im trying to use this

<?php
//We check if the users ID is defined
if(isset($_GET['id']))
{
    $id = intval($_GET['id']);
    //We check if the user exists
   
    $dn = mysql_query('SELECT * FROM members username, email_address, signup_date WHERE id="'.$id.'"');
   
    if(mysql_num_rows($dn)>0)
    {
        $dnn = mysql_fetch_array($dn);
        //We display the user datas
?>
Your Details: "<?php echo htmlentities($dnn['username']); ?>" :
</td>
        <td class="left"><h1><?php echo htmlentities($dnn['username'], ENT_QUOTES, 'UTF-8'); ?></h1>
        Email: <?php echo htmlentities($dnn['email'], ENT_QUOTES, 'UTF-8'); ?><br />
        This user joined the website on <?php echo date('Y/m/d',$dnn['signup_date']); ?></td>
    </tr>
</table>
<?php
    }
    else
    {
        echo 'This user dont exists.';
    }
}
else
{
    echo 'The user ID is not defined.';
}
?>

PHP:

To display certain info pulled from the database to display using echo. However the code keeps getting re-directed to echo 'The user ID is not defined.'; im not sure where the code has gone wrong.

        <?php
            session_start();
            include('db.php');
            print_r($_SESSION);
        ?>

PHP:

is running from the top of the html page.

if anyone can spare some time to help me out i would greatly appreciate it.

Thanks

 

Not to worry fixed ,

Registered Session Variables

        session_register('id');
        $_SESSION['id'] = $id;
        session_register('first_name');
        $_SESSION['first_name'] = $first_name;
        session_register('last_name');
        $_SESSION['last_name'] = $last_name;
        session_register('email_address');
        $_SESSION['email_address'] = $email_address;
        session_register('special_user');
        $_SESSION['user_level'] = $user_level;

PHP:

Then:

                <?php
                      echo  'Username ', $_SESSION['username'];
                      echo  "<br>";
                      echo  'email ', $_SESSION['email_address'];
                      echo  "<br>";
                      echo    'Joined on ', $S_SESSION['signup_date'];
                ?>

PHP:

This worked much easier and efficently! when your not loged in you wont see the page so no reason for else or die script/logic.

(posted fix for those if they need help fixing this problem one day)