Difference between dates by earliest date

Hi everyone,

Could someone please help me with this:

I’m creating a report in which I would like to show the difference in days between the date a product has become available for customers and the date of the first order of that product.

In Table ‘Products’, all products are listed once. I would like to add a column to this table called ‘DaysTillOrder’.

In Table ‘Orders’, all orders are listed. A product can be ordered multiple times.

The tables are linked by ProductID.

I’ve tried formulas to calculate the difference between dates. What I can’t figure out though, is how to calculate with the first Order date of a product only.

I’ve also tried to create a column with the minimum order date per product number as to calculate the difference from there. I ended up with the same minimum order date for every product, so something goes wrong there.

So I’m looking for the difference between CreationDate and earliest Orderdate per ProductID in days.

The structure looks like this:

Hope someone can help to find a good way to do this. It’s much appreciated!