php百万数据导出csv

<?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"');

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

//连接数据库
$dbhost = '127.0.0.1';
$dbuser = 'root';
$dbpwd = 'lsf123456';
$con = mysqli_connect($dbhost, $dbuser, $dbpwd);
if (mysqli_connect_errno()) {
die('connect error');
}
//选择数据库
$database = 'csdb';
mysqli_select_db($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 = 50;
$nums = 10000;

//设置标题
$title = array('编码','箱号连接','编码连接');
foreach($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 sncode,xiangcode FROM `zx` LIMIT {$start},{$nums}");

if($result) {
while($row = mysqli_fetch_assoc($result)) {
$row['xiangcode']='www.baidu.com?xx='.$row['xiangcode'];
$row['lianjie']='www.baidu.com?lianjie='.$row['sncode'];
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);