PHP と MySQL を使用して JSON データを Excel ファイルにインポートするにはどうすればよいですか?

<?php
require_once 'PHPExcel/Classes/PHPExcel.php';

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT json_data FROM table";
$result = $conn->query($sql);

$data = array();

if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        $data[] = $row['json_data'];
    }
}

$conn->close();

$objPHPExcel = new PHPExcel();

$objPHPExcel->setActiveSheetIndex(0);

$worksheet = $objPHPExcel->getActiveSheet();

$worksheet->setTitle('Sheet1');

$row = 1;

foreach ($data as $json) {
    $dataArray = json_decode($json, true);
    
    foreach ($dataArray as $col => $value) {
        $worksheet->setCellValueByColumnAndRow($col, $row, $value);
    }
    
    $row++;
}

$filename = 'data.xlsx';

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007');

$objWriter->save($filename);

echo "Excel file generated successfully.";