WB 2.08.x

                $sMessage = "<span>Updating group_id ".$TEXT['DISPLAY_NAME']." " .$aUsers[$user_id]['display_name']."</span>";

                $sql  = 'UPDATE `'.TABLE_PREFIX.'users` ';

                $sql .= 'SET `group_id`  = '.$group_id.', ';

                $sql .= 'WHERE `user_id` = '.intval($user_id);

                if($oRes = $database->query($sql)){  }