Create filter for sale items in category

I am trying to setup some filters for my shop and struggling with understanding how to do this. I have read and re-read the filters help page to no avail. the backend demo seems to have no filters to look at either.

so i have a clothes shop with a bunch of different categories (shirts, shorts, pants, skirts, dresses) and in those categories i have products which are full price and some that are on sale.

For the products on sale, I have created another category (called 'SALE') and added this category as well to the products being discounted (only way i could think of doing it as it isnt too easy to do with hikashop).

I want the ability for users when they are in each category (eg Shirts) to have a filter in a module on the left which they can click to filter out all the products not on sale and just leave the ones on sale. How do i do this? can you please make a screenshot to assist me.

thanks

Hi,

I think that the easiest way is to create a custom field in the table "Product" then in the product edition page fill this field with the value "sale" for the products in sale.
Then create a filter with a single dropdown type apply it on your custom field and add a value "sale" in the values.

the problem with this is that the discount function and the custom field are not only not connected they are in totally different locations to set.

discounts need to be within the product page so that a user can easily see what is discounted and whether or not this custom field 'sale' would need to be selected.

this is one thing Redshop had right that hikashop doesnt unfortunately.