Question

In MS Transact SQL, let’s say I have a table (Orders) like this:

 Order Date       Order Total     Customer #  09/30/2008       8.00            1  09/15/2008       6.00            1  09/01/2008       9.50            1  09/01/2008       1.45            2  09/16/2008       4.50            2  09/17/2008       8.75            3  09/18/2008       2.50            3 

What I need out of this is: for each customer the average order amount for the most recent two orders. So for Customer #1, I should get 7.00 (and not 7.83).

I’ve been staring at this for an hour now (inside a larger problem, which I’ve solved) and I think my brain has frozen. Help for a simple problem?

Answer 1

This should make it

select avg(total), customer  from orders o1  where orderdate in    ( select top 2 date      from orders o2      where o2.customer = o1.customer      order by date desc ) group by customer