php direct evaluation

[DannyV]

I'm pretty new to php coding, so bare with me.

What I'm trying to do is create in CMS a php direct evaluation evalutaion page that lists users from a certain usergroup.

Currently I've got this as code

$test=$db->query_read(SELECT userid,username from user WHERE usergroupid=10 ORDER BY username);
$output = "testusers<br />";
while ($row = $db->fetch_array($test)) {
$output .= "$row['username']<br />";
};
$output .= "done<br />";

But I don't get any output from that.
Anybody that can push me in the right direction ?