PHP从SQL获取带有子数组的数组

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

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

// 查询语句
$sql = "SELECT users.id, users.name, orders.order_id, orders.product
        FROM users
        LEFT JOIN orders ON users.id = orders.user_id";

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

$data = array();

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        if (!isset($data[$row['id']])) {
            $data[$row['id']] = array(
                'id' => $row['id'],
                'name' => $row['name'],
                'orders' => array()
            );
        }
        $data[$row['id']]['orders'][] = array(
            'order_id' => $row['order_id'],
            'product' => $row['product']
        );
    }
} else {
    echo "0 结果";
}

$conn->close();

// 打印结果
print_r($data);
?>