Subtracting one row of data from another in SQL

Question

I\'ve been stumped with some SQL where I\'ve got several rows of data, and I want to subtract a row from the previous row and have it repeat all the way down.

So her

Answer 1

What about something like this:

SELECT T2.ID, T2.[Length], T2.[Length]-T1.[Length] AS 'Difference'
FROM Foo AS T1 RIGHT OUTER JOIN Foo AS T2 ON ( T1.ID = (T2.ID-1) )
ORDER BY T1.ID