我有一个问题。我想按说明订购邮递。

case 'posts':
        // page header
        page_header($system['system_title'].' - '.__("Posts Directory"));

        // pager config
        require('includes/class-pager.php');
        $params['selected_page'] = ( (int) $_GET['page'] == 0) ? 1 : $_GET['page'];
        $total = $db->query("SELECT * FROM posts") or _error(SQL_ERROR);
        $params['total_items'] = $total->num_rows;
        $params['items_per_page'] = $system['max_results'];
        $params['url'] = $system['system_url'].'/directory/'.'posts'.'/%s';
        $pager = new Pager($params);
        $limit_query = $pager->getLimitSql();

        // get posts
        $rows = array();
        $get_rows = $db->query("SELECT post_id FROM posts ".$limit_query) or _error(SQL_ERROR);
        while($row = $get_rows->fetch_assoc()) {
            $row = $user->get_post($row['post_id']);
            if($row) {
                $rows[] = $row;
            }
        }
        $smarty->assign('rows', $rows);
        $smarty->assign('pager', $pager->getPager());
        break;

我可以试着按邮政编码订购吗？请回答我的问题。