any chance you can upload a version of your file that is ok to share (in terms of data privacy)? hard to tell what you are trying to do without seeing your model and measures. It sounds like you need a dimension table, that can be easily generated with the SUMMARIZE() or VALUES() function. It looks like here you need to enter a new table with DAX using VALUES(‘sales history’[product id]) but you’ll also need a date table, you can enter one into power query using this query described here:
After you have both of those you need to create one to many relationships between both of your sales tables to the date table and newly made product table, learn about that here https://www.youtube.com/watch?v=xGFbLvs31Io&t=1s
but it’d probably be good if you do the whole beginners guide to power bi on youtube that I linked above, it’s a great series, I did it myself 3 years ago!
hope that helps.
Tim