<?php
/**
 * 大量数据导出excel（csv）的实现。
 * Created by PhpStorm.
 * User: Huming
 * Date: 2017-04-16
 * Time: 14:04
 *  */

//使用MS sqlserver数据测试的
require_once ‘MSSqlServerHelper.php‘;
$sqlHelper = new MSSqlServerHelper();
set_time_limit(0);
ini_set(‘memory_limit‘, ‘128M‘);

date_default_timezone_set("PRC");
$fileName = date(‘YmdHis‘);

//浏览器直接下载，加头文件
//header(‘Content-Type: application/vnd.ms-execl‘);
//header(‘Content-Disposition: attachment;filename="‘ . $fileName . ‘.csv"‘);

$begintime = microtime(true);

//打开php标准输出流
//以写入追加的方式打开
//$fp = fopen(‘php://output‘, ‘ab‘);
//对于大数据，使用在服务器生成文件，完成后下载
$path = $_SERVER[‘DOCUMENT_ROOT‘] . "\\output\\";

$fp = fopen("$path$fileName.csv", "a");


//我们要获取$nums条数据，每次取$step条，分步执行，避免内存溢出
//如果线上环境无法支持一次性读取$step条数据，可反$step相应减小。
$step = 10000;
//指定要取的记录数
//$nums =80000;
//动态获取总共的记录数
$rowscount = $sqlHelper->execute_dql_rowsCount("select count(id)  from temp_sjbb");
$nums = $rowscount;
//$nums = 22;



//设置标题
/*$title = array(‘ID‘, ‘用户名‘, ‘用户年龄‘, ‘用户描述‘, ‘用户手机‘, ‘用户QQ‘, ‘用户邮箱‘, ‘用户地址‘);
foreach($title as $key => $item) {
    $title[$key] = iconv(‘UTF-8‘, ‘GBK‘, $item);
}
//标题写到标准输出中
fputcsv($fp, $title);*/


//分批获取，写入大数据，防止内存溢出
for ($s = 1; $s <= ceil($nums / $step); ++$s) {
    $start = (($s - 1) * $step) + 1;
    $end = ($s * $step) > $nums ? $nums : $s * $step;

    $sql = "select * from (select *,rOW_NUMBER() OVER (ORDER BY id asc) AS counts  from temp_sjbb ) as b";
    $sql .= " where counts >= ";
    $sql .= $start;
    $sql .= " and counts <= ";
    $sql .= $end;
    // echo  $sql;
    $result = $sqlHelper->execute_dql_array($sql);

    for ($i = 0; $i < count($result); $i++) {

        //第一次循环把列标题打印出来
        if ($s == 1 && $i == 0) {
            $arr = array();
            foreach ($result[$i] as $key => $values) {
                $arr[] = $key;
            }
            fputcsv($fp, $arr);
        }

        fputcsv($fp, $result[$i]);
    }


    //刷新缓冲区
    unset($result);
    ob_flush();
    flush();
}
fclose($fp);

//打印下载路径
echo "<a href=http://www.mamicode.com/‘./output/$fileName.csv‘>点击下载";

$endtime = microtime(true);
echo ‘用时：‘, $endtime - $begintime;