<?php

set_time_limit(0);

ini_set('memory_limit', '128M');

$fileName = date('YmdHis', time());

header('Content-Encoding: UTF-8');

header("Content-type:application/vnd.ms-excel;charset=UTF-8");

header('Content-Disposition: attachment;filename="' . $fileName . '.csv"');

//打开php标准输出流

//以写入追加的方式打开

$fp = fopen('php://output', 'a');

//连接数据库

$dbhost = '127.0.0.1';

$dbuser = 'root';

$dbpwd = '';

$con = mysqli_connect($dbhost, $dbuser, $dbpwd);

if (mysqli_connect_errno()) {

   die('connect error');

}

//选择数据库

$database = 'test';

mysqli_select_db($con, $database);

//设置编码

mysqli_query($con, "set names UTF8");

//我们试着用fputcsv从数据库中导出1百万的数据

//我们每次取1万条数据，分100步来执行

//如果线上环境无法支持一次性读取1万条数据，可把$nums调小，$step相应增大。

$step = 100;

$nums = 10000;

$where = ""; //筛选条件

//设置标题

$title = array('ID','姓名‘,'年龄','性别');

foreach($title as $key => $item) {

    $title[$key] =iconv("UTF-8", "GBK", $item);

}

//将标题写到标准输出中

fputcsv($fp, $title);

for($s = 1; $s <= $step; $s++) {

    $start = ($s - 1) * $nums;

    $result = mysqli_query($con,"SELECT * FROM `test` ".$where." ORDER BY `id` LIMIT {$start},{$nums}");

    if($result) {

        while($row = mysqli_fetch_assoc($result)) {

            foreach($row as $key => $item) {

                //这里必须转码，不然会乱码

                $row[$key] = iconv("UTF-8", "GBK", $item);

            }

            fputcsv($fp, $row);

        }

        mysqli_free_result($result); //释放结果集资源

        //每1万条数据就刷新缓冲区

        ob_flush();

        flush();

    }

}

//断开连接

mysqli_close($con);