Problem med sql/php

SELECT *, max(m.date) as maxdate
FROM test.mail as m, test.user as u
WHERE m.to_id = u.id
GROUP BY from_id
ORDER BY maxdate

<?php
$userid = 7;// id for den bruger der er logget ind
function db_connect(){
    mysql_connect("localhost", "user", "password") or die(mysql_error());
    mysql_select_db("test") or die(mysql_error());
}
db_connect();
$result = mysql_query("
                        SELECT * , MAX( m.date ) AS maxdate
                        FROM test.mail AS m, test.user AS u
                        WHERE m.to_id = u.id
                        AND m.not_read = 0
                        AND u.id = ".$userid."
                        GROUP BY from_id
                        ORDER BY maxdate DESC
                                            ")or die(mysql_error());

while($row = mysql_fetch_array($result)){
    echo $row['message'].'<br />'; 
}
?>