php导出百万数据到csv

<?php

    set_time_limit(0);      // 设置超时

    ini_set('memory_limit', '100M');       // 设置最大使用的内存

    header("Content-type:text/csv");

    header("Content-Disposition:attachment;filename=" . date('Ymd'). '.csv');

    header('Cache-Control:must-revalidate,post-check=0,pre-check=0');

    header('Expires:0');

    header('Pragma:public');

    $out = fopen('php://output', 'w');

    $bom = chr(0xEF).chr(0xBB).chr(0xBF);     // 防止乱码

    $func = function ($list){

        $arr = [];

        foreach ($list as $v){

            $arr[$v['id']] = $v['name']

        }

        return $arr;

    }

     // todo 注意我这里都是用sql语句直接代替查询

    $list = select * from area;

    $area = $func($list);

    $list = select * from greate;

    $greate = $func($list);

    $list = select * from School;

    $School = $func($list);

    ob_end_clean();

    ob_implicit_flush(5);

    fputcsv($out, [$bom . '学生编号','学生姓名','所属区域','所属年级','所属学校']);

    // 上面整理好了对应关系

    do{

        $i = 0;

        $list = select * from student where id > $i order by id asc limit 10000

        if(!$list) break;

        foreach($list as $v){

            if($v['id'] > $i) $i = $v['id'];    // 这里可以不这样写，这些就自己优化吧

            fputcsv($out, [

                        $v['student_no'],$v['name'],

                        $area[$v['areaId']],

                        $greate[$v['gradeId']],

                        $School[$v['SchoolId']],

                    ]);

        }

    }while(true)

    fclose($out);

    exit();