CREATE TABLE `tb_users` (
 `id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '用户ID',
 `name` varchar(32) DEFAULT '' COMMENT '用户名',
 `age` tinyint(3) DEFAULT '0' COMMENT '用户年龄',
 `desc` varchar(255) DEFAULT '' COMMENT '用户描述',
 `phone` varchar(11) DEFAULT '' COMMENT '用户手机',
 `qq` varchar(16) DEFAULT '' COMMENT '用户QQ',
 `email` varchar(64) DEFAULT '' COMMENT '用户邮箱',
 `addr` varchar(255) DEFAULT '' COMMENT '用户地址',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

<"(NULL, '{$name}', $age, '{$desc}', '{$phone}', '{$qq}', '{$email}', '{$addr}'),";
  }
  $insSql = rtrim($insSql, ',');
  $db->query($insSql);
}
$end = microtime(true);
echo '用时:', $end - $begin;

$db->close();

<"' . $fileName . '.csv"');

$begin = microtime(true);

//打开php标准输出流
//以写入追加的方式打开
$fp = fopen('php://output', 'a');

$db = new mysqli('127.0.0.1', 'root', '', 'test');

if($db->connect_error) {
  die('connect error');
}

//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;

//设置标题
$title = array('ID', '用户名', '用户年龄', '用户描述', '用户手机', '用户QQ', '用户邮箱', '用户地址');
foreach($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 = $db->query("SELECT * FROM tb_users ORDER BY id LIMIT {$start},{$nums}");
  
  if($result) {
    while($row = $result->fetch_assoc()) {
      foreach($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);
    }
    $result->free();
    
    //每1万条数据就刷新缓冲区
    ob_flush();
    flush();
  }
}

$end = microtime(true);
echo '用时：', $end - $begin;

<a href="/downSearchData.php" rel="external nofollow" >下载汇总结果1</a>
<a href="/downSearchData.php" rel="external nofollow" >下载汇总结果2</a>
<a href="/downSearchData.php" rel="external nofollow" >下载汇总结果3</a>

<form id="searchFrm">
  姓名<input type="text" name="uname">
  <input type="button" id="searchDataBtn" value="导出汇总结果">
</form>
<div id="searchDataList"></div>

<script type="script">
  $("#searchDataBtn").on("click", function() {
    var params = $("#searchFrm").serialize();
    
    //获取查询数据的条数
    $.get("/getSearchDataRows" + params, function(data) {
      var downDataList = "";
      if(data["rows"]) {
        //rows是数据总条数，pageSize是一页多少条
        var pageNum = Math.ceil(data["rows"] / data["pageSize"]);
        for(var i = 1; i <= pageNum; ++i) {
          downDataList += "<a href='/downSearchData.php" + params + "&page=" + i + ">下载汇总结果" + i + "</a>&nbsp;&nbsp;";
        }
        $("#searchDataList").html(downDataList);
      } else {
        $("#searchDataList").text("没有数据");
      }
    }, "json");
    return false;
  });
</script>