$query = "
select distinct(t1.USER_ID)
from {$config['TABLE_PREFIX']}USER_GROUPS as t1,
{$config['TABLE_PREFIX']}POSTS as t2
where t1.USER_ID = t2.USER_ID
and t1.GROUP_ID = 6
and t2.TOPIC_ID = ?
";
$sth = $dbh -> do_placeholder_query($query,array($topic_info['TOPIC_ID']),__LINE__,__FILE__);
$graphicusers = array();
while (list($graphicuserid) = $dbh -> fetch_array($sth)) {
$graphicusers[] = $graphicuserid;
}