Calculating the deltas in weekly sales

[ficklelife]

I have a table Sales which contains data such as:

[TABLE="width: 500"]
<tbody>[TR]
[TD]id[/TD]
[TD]date[/TD]
[TD]name[/TD]
[TD]Amount[/TD]
[/TR]
[TR]
[TD]123[/TD]
[TD]2016-04-21 14:22[/TD]
[TD]Jims Nuts[/TD]
[TD]200[/TD]
[/TR]
</tbody>[/TABLE]

I have visualised my weekly sales by creating a new column with the formula

week_number = WEEKNUM('Sales'[date])

which gives me a column with 1,2,3 etc based on the week it was sold based on date column.

I would then like to visualise in a waterfall chart the deltas week to week in sales - e.g. Sales in week 3 compared to week 2 is 20k deficit, week 4 compared to 3 is 30k up, etc... How would I write a DAX query to visualise this data?

 

[sadath]

Hi

create new calculated column name WEEKNUMBER using =WEEKNUM([date])

to get week 1 total Week1Tot:=calculate(sum(Table1[Amount]),filter(table1,Table1[WeekNumber]=1))
to get week 2 total Week2Tot:=calculate(sum(Table1[Amount]),filter(table1,Table1[WeekNumber]=2))

Deficit Deficit WK2 Vs Wk 1:=[Week2Tot]-[Week1Tot]

so on...