php - 从数据库导出百万级数据(CSV文件)

将数据库连接信息、查询条件、标题信息替换为真实数据即可使用。

 <?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);