>No, I don't want :-)
>Why should I?
>I want to get to this range where the Overweight belongs.
>the PreviousAmount column contains the total of ALL previous ranges and I need to calculate only difference between the Overweight and MinRange.

I see now, OK. So either of the ideas will work, but I like George's for its simplicity and no need for an extra column.

On the other hand, with the PreviousTotalAmount will work quicker - less records to join.