this week versus last week difference

[gheecalipes25]

I have a table below in which i wanted to calculate or get the difference from this week's count against last week. below is a sample table output that i wanted to achieve. i wanted to get a dax formula for the Week Difference. Thank you in advance.

CountOfECMs	WEEKENDINGSAT	Week Difference
21	12/2/2017
30	12/9/2017	9
33	12/16/2017	3
11	12/23/2017	-22
8	12/30/2017	-3
11	1/6/2018	3
25	1/13/2018	14
32	1/20/2018	7
16	1/27/2018	-16
17	2/3/2018	1
25	2/10/2018	8
20	2/17/2018	-5
22	2/24/2018	2
19	3/3/2018	-3
17	3/10/2018	-2

[v-easonf-msft · Accepted solution]

Hi, @gheecalipes25 

Please try formula like:

Week Difference = 
VAR last_week =
    CALCULATE (
        MAX ( 'Table'[WEEKENDINGSAT] ),
        FILTER (
            ALL ( 'Table' ),
            'Table'[WEEKENDINGSAT] < MAX ( 'Table'[WEEKENDINGSAT] )
        )
    )
VAR _count_of_lastweek =
    CALCULATE (
        [CountOfECMs1],
        FILTER ( ALL ( 'Table' ), 'Table'[WEEKENDINGSAT] = last_week )
    )
RETURN
    IF (
        ISBLANK ( _count_of_lastweek ),
        BLANK (),
        [CountOfECMs1] - _count_of_lastweek
    )

Best Regards,
Community Support Team _ Eason

[Greg_Deckler]

@gheecalipes25 Easiest way would be to use a Sequential column: Sequential - Microsoft Power BI Community