In that case, you want to use a recursive CTE.  I don't have the time right now to look at it.

Drew

LEAD/LAG will not work, because you need to specify the distance from the current row, and the distance isn't constant.  You also made it more difficult to see the correct...

I updated this to remove an expensive sort.  The SUM was sorting ascending by the date, but the...

There is a third option.  I don't have the time right now to do a comparison.

select (serno * 100) / NULLIF(100 - bargain, 0) from yachtm

In order for the CROSS APPLY to replicate ROWS UNBOUNDED PRECEDING, you'll need a triangular join.  You're better off using a quirky update in SQL 2008.

Drew

That's way too many reads (12) on the base table.  Here is an approach that requires only ONE read.

;
WITH Ordered_Appts AS
(
    SELECT *,
        DATEADD(MONTH,...