Relation/lookup value DESC

I have two tables:

  1. user

For each purchase, there are many columns but two of them are the most relevant:
1)email of the user
2) a unique link

I want to add a column in the user table that will automatically be filed by the LAST (newest) link of the purchase for each user.

So for example, Bob bought a book. So I will have a new row in the purchase table with Bob’s email and a unique link and date of purchase.
Now I need to find a way that will copy the link to the column in the user table that calls (for example) “last link of purchase”

It’s not a regular relation, because I need to have the relation on the newest row.

How can I do it? What am I missing?

Create a multiple relation linking the email in the user table to the email in the purchase table. Then create a Single Value column that retrieves the last link from the relation.