Howto get info from a mysql query? Resource ID #23 is all I get

[Mephisteus]

I have this query: $activeusers = $DB_site->query("
SELECT user.*, usergroup.*
FROM " . TABLE_PREFIX . "user AS user
LEFT JOIN " . TABLE_PREFIX . "usergroup AS usergroup ON(usergroup.usergroupid=user.usergroupid)
WHERE user.tsserver_timestamp != ''
ORDER BY usergroup.orderid DESC, user.username ASC
");

This returns "Resource id #23". Now this may sound stupid, but how do I get info from that?

PS
If it's in the wrong part, sorry, was kind of unsure where to put it since I got the query, just not the php :P