Special Price vs Regular Price in an Order

[Ramallama]

How can I determine from an order if the special price was used or the regular price?  I need to be able to provide a report items sold using the sale price.  We cannot use the product information as prices change constantly.

[Peter Uhlich]

Short answer: You cannot.
Since information about the price type is not saved to order or order_item, this request is impossible.

You need a feature for this, that converts this information from the product through the quote item to the order item.