rolling sum: empty values in groups

[WillemC]

Hi all,

I got a problem I can't wrap my head around.

I'm trying to create a rolling sum for the past 12 weeks.

I got sales data, which consists out of salesdate, productgroup, amount etc.

I created a datetable, which contains year-week numbers, first day of the week for a date, last date of the week for a date etc.

This datetable is over the same period as the salesdates, so that I have ALL the dates available.

In the salesdata, dates may be missing due to no sales, weekends etc.

My datatable:

Datumtabel = ADDCOLUMNS(
    CALENDAR( min(OMZETFEED[LEVDAT]) ; DATE( YEAR(TODAY() );12;31) ) ;
    "Jaar";year( [Date] );
    "Maandomschr."; FORMAT( [Date] ; "mmm");
    "Maandnr" ; month( [Date] );
    "Kwartaal-Jaar"; format( [Date] ; "\QQ") & "-" & year([Date]);
    "ISOWeeknr" ; WEEKNUM([Date];21);
    "ThisYear" ; if ([Date] >= DATE(YEAR(TODAY());1;1) && [Date] <= TODAY(); 1; 0);
    "Weekend/werkdag" ; if(WEEKDAY([Date];2)<6;"Werkdag" ; "Weekend");
    "Iso Year" ; IF( AND(WEEKNUM([Date];21) < 5;WEEKNUM([Date];2) > 50);year([Date])+1;IF(AND(WEEKNUM([Date];21) > 50;WEEKNUM([Date];2) < 5);year([Date])-1;year([Date])));
    "Week-Jaar"; IF( AND(WEEKNUM([Date];21) < 5;WEEKNUM([Date];2) > 50);year([Date])+1;IF(AND(WEEKNUM([Date];21) > 50;WEEKNUM([Date];2) < 5);year([Date])-1;year([Date]))) & 
    if(
    Weeknum([Date];21)<10;"0";blank())&WEEKNUM([Date];21);
    "WeekEndDate";[Date]-MOD([Date]-1;7)+7;
    "WeekStartDate";[Date]-MOD([Date]-1;7)+1
     )

When I create a rolling sum over the past 12 weeks (7x12=84 days) and I split these up in the productGroups, some groups show empty values in a matrix for the week in which they haven't been sold.

So for example, in week 12 there has been no sales for productgroup D. The matrix and graphs show a blank value.

But instead I want to show the sum of the weeks 1-12 (as soon as one week has a sale, during the next 12 weeks there should always be a value).

Only if a productgroup hasn't been sold during 12 weeks, then it's allowed to show blank or null, because sum sales over the last 12 weeks have indeed been none.

How should I do this? I tried different DAX formulas, but I'm not able to get this working.

I prefer to use full weeks, that's why I added the lastdate (of the week that date is in).

[WillemC · Accepted solution]

Okay, seems that I found the solution.

I was using a column value to calculate instead of a measure...

The following measure did what I wanted (except it allready creates a sum for the future 12 weeks)
But this I could solve by filtering the matrix/graph to end at the current week.

SUM Last 3M = 
CALCULATE (
    SUM( Sales[WEIGHT] );
    FILTER(ALL(Datumtabel[Date]);
          Datumtabel[Date] <= MAX(Datumtabel[Date]) 
          &&  
          DATEADD(Datumtabel[Date];84;DAY) >= MAX(Datumtabel[Date]      
    )
     )
      )

Little side note, it's posible to use MIN instead of MAX, then it shows the sum of the previous 12 weeks instead of current + 11 weeks earlier.

[WillemC]

Just one more note. Because of the extra weeks added, which I didn't want, I altered my calendar code and SUM-code.

The datetable code has been altered, so the last day created in this datatable, is the last weekday of the maximum salesdate:

Datumtabel = ADDCOLUMNS(
    CALENDAR( min(OMZETFEED[LEVDAT]) ; max(OMZETFEED[LEVDAT])-MOD(max(OMZETFEED[LEVDAT])-1;7)+7 ) ;
    "Jaar";year( [Date] );
    "Maandomschr."; FORMAT( [Date] ; "mmm");
    "Maandnr" ; month( [Date] );
    "Kwartaal-Jaar"; format( [Date] ; "\QQ") & "-" & year([Date]);
    "ISOWeeknr" ; WEEKNUM([Date];21);
    "ThisYear" ; if ([Date] >= DATE(YEAR(TODAY());1;1) && [Date] <= TODAY(); 1; 0);
    "Weekend/werkdag" ; if(WEEKDAY([Date];2)<6;"Werkdag" ; "Weekend");
    "Iso Year" ; IF( AND(WEEKNUM([Date];21) < 5;WEEKNUM([Date];2) > 50);year([Date])+1;IF(AND(WEEKNUM([Date];21) > 50;WEEKNUM([Date];2) < 5);year([Date])-1;year([Date])));
    "Week-Jaar"; IF( AND(WEEKNUM([Date];21) < 5;WEEKNUM([Date];2) > 50);year([Date])+1;IF(AND(WEEKNUM([Date];21) > 50;WEEKNUM([Date];2) < 5);year([Date])-1;year([Date]))) & 
    if(
    Weeknum([Date];21)<10;"0";blank())&WEEKNUM([Date];21);
    "WeekEndDate";[Date]-MOD([Date]-1;7)+7;
    "WeekStartDate";[Date]-MOD([Date]-1;7)+1
     )

I've altered the measure to the following code, to get the correct sum values of that week and previous 12 weeks (so 13 weeks in total):

SUM Last 13WKS = 
CALCULATE (
    SUM( OMZETFEED[GEWICHT] );
          DATESBETWEEN(Datumtabel[Date];FIRSTDATE(DATEADD(Datumtabel[Date];-84;DAY));LASTDATE(Datumtabel[Date])
    ))

 
This is the result of the start & end period created with this formula:
To create this table create 2 measures:

FirstDate = FIRSTDATE(DATEADD(Datumtabel[Date];-84;DAY))

and a measure:

LastDate = LASTDATE(Datumtabel[Date])