如何用PHP创建sql文件并在sql文件中动态写入查询？

$servername = "数据库服务器地址";
$username = "数据库用户名";
$password = "数据库密码";
$dbname = "数据库名";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

$sql = "SELECT * FROM 表名";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "字段1: " . $row["字段1名称"]. " - 字段2: " . $row["字段2名称"]. "<br>";
    }
} else {
    echo "0 结果";
}

$sql = "SELECT * FROM 表名";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 打开文件
    $file = fopen("查询结果.sql", "w");

    // 写入查询结果到文件
    while($row = $result->fetch_assoc()) {
        $line = "字段1: " . $row["字段1名称"]. " - 字段2: " . $row["字段2名称"]. "\n";
        fwrite($file, $line);
    }

    // 关闭文件
    fclose($file);

    echo "SQL文件创建成功";
} else {
    echo "0 结果";
}