php excel导出大量数据方法

参考:https://segmentfault.com/a/1190000011663425

https://segmentfault.com/a/1190000014483949  这个需要安装扩展

        set_time_limit(-1);
        @ini_set('memory_limit','512M');
        $columns = ['文章ID', '文章标题'];
        $fileName = 'orderlog' . '.csv';
        //设置好告诉浏览器要下载excel文件的headers
        header('Content-Description: File Transfer');
        header('Content-Type: application/vnd.ms-excel');
        header('Content-Disposition: attachment; filename="'. $fileName .'"');
        header('Expires: 0');
        header('Cache-Control: must-revalidate');
        header('Pragma: public');
        $fp = fopen('php://output', 'a');//打开output流
        fputcsv($fp, $columns);//将数据格式化为CSV格式并写入到output流中

        $query = new Query();
        $orderModel = $query->select("*")
            ->from("{{%tuan_forum_thread}}")
            ->orderBy('tid asc')
            ->limit(80000) ;

        foreach ($orderModel->batch(100) as $orders) {
            foreach ($orders as $order) {
                $rowData = [
                    $order['tid'], "\t" .$order['subject'],
                ];
                fputcsv($fp, $rowData);
            }
            ob_flush();
            flush();//必须同时使用 ob_flush() 和flush() 函数来刷新输出缓冲。
        }

        fclose($fp);
        exit();