PHP：买两个并节省50美元？-PHP:Buybothandsave$50?

Why not perform the check right before they submit the order? that way, everytime they get to the submit order page, it will check if both items are present.

为什么不在提交订单之前立即执行检查?这样,每当他们到达提交订单页面时,它将检查两个项目是否都存在。

easy enough - always calculate the final price on the fly based on the current cart contents. The issue you mention seems like it would only be a problem if you were calculating the final price and caching it somehow.

足够简单 - 始终根据当前购物车内容计算最终价格。您提到的问题似乎只是在计算最终价格并以某种方式缓存它时才会出现问题。

usualy it'd done by creating a new bundle item. It's a bit dirty but works :)

通常它是通过创建一个新的捆绑项来完成的。它有点脏,但工作:)

Are they using a system already, or is this a custom job on your part?

他们是否已经使用过系统,或者这是您自己的定制工作?

Add the discount to the cart and use another table to keep track of the discount's dependencies. Whenever an item is removed from the cart, check to make sure the discount is still valid. If it is, great. If not, remove it and recalculate the cart price.

将折扣添加到购物车并使用另一个表来跟踪折扣的依赖关系。每当从购物车中移除商品时,请检查以确保折扣仍然有效。如果是的话,很棒。如果没有,请将其删除并重新计算购物车价格。