以流的形式从php导出到csv

<?php
// 连接数据库或获取数据
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 查询数据
$sql = "SELECT column1, column2, column3 FROM table";
$result = $conn->query($sql);

// 设置HTTP头部
header('Content-Type: text/csv');
header('Content-Disposition: attachment; filename="data.csv"');

// 创建输出流
$output = fopen('php://output', 'w');

// 写入CSV文件头部
fputcsv($output, array('Column 1', 'Column 2', 'Column 3'));

// 写入数据行
while ($row = $result->fetch_assoc()) {
    fputcsv($output, $row);
}

// 关闭输出流
fclose($output);

// 关闭数据库连接
$conn->close();
?>