php pdo 鏈接數據庫

/鏈接數據庫
        $servername = "localhost";
        $username = "root";
        $password = "111111";
        try {
            $conn = new PDO("mysql:host=$servername;dbname=kuaijiezhou", $username, $password);
            $conn->exec("SET NAMES 'utf8';");    
            //echo "Connected successfully"; 
        }
        catch(PDOException $e)
        {
            echo $e->getMessage();
        }
	$orderid = $_GET['orderid']  ? intval($_GET['orderid']) : ''; //用戶id
        //查詢訂單
        $url1 = "SELECT * FROM my_order where id = $orderid";
        $res_order = $conn->query($url1)->fetch(PDO::FETCH_ASSOC);
        //訂單配送時間
        $url2 = "SELECT * FROM my_ordersendtime where orderid = $orderid";
        $res_order_sendtime = $conn->query($url2)->fetch(PDO::FETCH_ASSOC);
        //訂單詳情
        $url3 = "SELECT * FROM my_orderdetail where orderid = "."'".$res_order['orderid']."'";
        $res_order_detail = $conn->query($url3)->fetchAll(PDO::FETCH_ASSOC);