<?php
  //讓程序一直運(yùn)行
  set_time_limit(0);
  //設(shè)置程序運(yùn)行內(nèi)存
  ini_set('memory_limit', '128M');
 
  $fileName = '測(cè)試導(dǎo)出數(shù)據(jù)';
  header('Content-Encoding: UTF-8');
  header("Content-type:application/vnd.ms-excel;charset=UTF-8");
  header('Content-Disposition: attachment;filename="' . $fileName . '.csv"');
  
  //打開(kāi)php標(biāo)準(zhǔn)輸出流
  $fp = fopen('php://output', 'a');
 
  //添加BOM頭，以UTF8編碼導(dǎo)出CSV文件，如果文件頭未添加BOM頭，打開(kāi)會(huì)出現(xiàn)亂碼。
  fwrite($fp, chr(0xEF).chr(0xBB).chr(0xBF));
  //添加導(dǎo)出標(biāo)題
  fputcsv($fp, ['姓名', '年齡', '地區(qū)']);
  
  //鏈接數(shù)據(jù)庫(kù)
  $dsn = "mysql:host=127.0.0.1;port=3306;dbname=db_www;charset=utf8";
  $pdo = new PDO($dsn, 'root', '');
 
  $step = 100; //循環(huán)次數(shù)
  $nums = 10000; //每次導(dǎo)出數(shù)量
 
  for($i = 0; $i < $step; $i++) {
    $start = $i * 10000;
    $sql = "SELECT uname,age,city FROM `hd_test` ORDER BY `id` LIMIT {$start},{$nums}";
    $pdostatement = $pdo->query($sql);
    $result = $pdostatement->fetchAll(PDO::FETCH_ASSOC);
    foreach ($result as $item) {
      fputcsv($fp, $item);
    }
    //每1萬(wàn)條數(shù)據(jù)就刷新緩沖區(qū)
    ob_flush();
    flush();
  } 

INSERT INTO hd_test (uname,age,city) SELECT uname,age,city FROM hd_test;