尝试收集购物车中的产品总和

Question

当我运行代码时，下面的代码没有显示总价，它只返回“总价：£”。任何帮助都会有所帮助。

<?php
// Create a PDO connection to the database
$dbh = new PDO("mysql:host=".DB_HOST.";dbname=".DB_NAME, DB_USER, 
DB_PASS);
$id = $_POST['id'];

// Prepare a SQL statement to select the total of the price column
$stmt = $dbh->prepare('SELECT SUM(hotel_price) as total FROM products 
WHERE user_id = :user_id');

// Execute the statement
$stmt->execute([
  "user_id" => $_SESSION['user_data']['user_id'],
]);

 // Fetch the total as an associative array
$total = $stmt->fetch(PDO::FETCH_ASSOC)['total'];

// Display the total
echo "Total price: £$total";
?>