week to week differense calculation

[#1]

Hi everybody! Explored many topics with similar or alike titles but didn't find right solution. The problem is to calculate the difference between weeks in straight table. In most topics have been discussed there is a selection of 2 definite periods (usualy year to year). In my case I select 1 period (e.g. January 2014) and have to get such table

Week	Sales	Growth
1	100	0
2	150	50
3	120	-30
4	160	40

So the problem is,that I can't compute the difference between weeks in 1 month.

I tried formula like this:

= sum({$}Sales) - sum({$<Week={Week-1}>}Sales), but it didn't work. Week numbers are in my calendar. I feel that solution is simple,but can't find it. Can anybody help me?

[MK_QSL]

Sales

SUM(Sales)

Growth

SUM(Sales)-Above(SUM(<Month>Sales)

or

SUM(Sales)-Above(SUM(Sales)

[PradeepReddy · Accepted solution]

As per my understanding...

sum(Sales)-above(sum(Sales))

[#4]

This way also was tried. But functions above() and before() can be used only in charts ot pivot tables

[#5]

Мy apologies! Guys, it works! Thanks a lot!