need little help

[Richardtagger]

<?
session_start();
include 'db.php';
$id = intval($GET['msg']);
$query = mysql_query("SELECT message FROM mail WHERE id=$id AND touser=$SESSION[username]");
$result = mysql_result($query,0,"message");
echo $result;
?>

i dont knwo whats wrong here i am not very good with the mysql_result. It says its an invalid resource.

[TheDefender]

$query = mysql_query("SELECT message FROM mail WHERE id='$id' AND touser='".$_SESSION['username']."'");