dedecms制作购物车

<?php
// 获取当前用户的Session ID
$session_id = session_id();

// 查询数据库中该用户的购物车信息
$sql = "SELECT * FROM `dede_shopping_cart` WHERE `session_id` = '$session_id'";
$result = mysqli_query($conn, $sql);

// 处理查询结果
while ($row = mysqli_fetch_assoc($result)) {
    echo "商品ID: " . $row['product_id'] . ", 数量: " . $row['quantity'] . "<br>";
}

// 添加商品到购物车
if (isset($_POST['add_to_cart'])) {
    $product_id = $_POST['product_id'];
    $quantity = $_POST['quantity'];

    // 查询当前用户购物车中是否已有该商品
    $sql_check = "SELECT * FROM `dede_shopping_cart` WHERE `session_id` = '$session_id' AND `product_id` = '$product_id'";
    $result_check = mysqli_query($conn, $sql_check);

    if (mysqli_num_rows($result_check) > 0) {
        // 更新商品数量
        $sql_update = "UPDATE `dede_shopping_cart` SET `quantity` = `quantity` + $quantity WHERE `session_id` = '$session_id' AND `product_id` = '$product_id'";
    } else {
        // 插入新商品
        $sql_insert = "INSERT INTO `dede_shopping_cart` (`session_id`, `product_id`, `quantity`) VALUES ('$session_id', '$product_id', $quantity)";
    }

    mysqli_query($conn, $sql_update ? $sql_update : $sql_insert);
}
?>

<!-- 购物车表单 -->
<form method="post">
    <input type="hidden" name="add_to_cart" value="1">
    商品ID: <input type="text" name="product_id"><br>
    数量: <input type="text" name="quantity"><br>
    <input type="submit" value="添加到购物车">
</form>