Previous value for same day last week and last week

[po]

Hi,

We have a sales table which will have many weeks worth of data in it

YearWeek

Shop

Day

Amount Supplied

Amount Sold

and wish to show for each day of week the amount sold for the corresponding day of the previous week

when view at day level

YearWeek  Shop   Day    Amount Sold  Previous Amount Sold

201901       A        SUN     100                50

Similarly when view at week level wish to show the amount sold for the previous week.

How is this best achieved?

Have used below in past but this not working here and wonder if better approach

calculate(SUMX(sales,sales[amount sold]) ,filter(all
(calendar),calendar[Date]=MAX(calendar[Date])-7) )

When use above just shows a value for one week - other weeks blank.

[Greg_Deckler]

If you want to do this as a column you might look into EARLIER. See my article on Mean Time Before Failure (MTBF) which uses EARLIER: http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/3395...

Also see if my Time Intelligence the Hard Way provides a different way of accomplishing what you are going for.

https://community.powerbi.com/t5/Quick-Measures-Gallery/Time-Intelligence-quot-The-Hard-Way-quot-TIT...

Finally, you might want to use Sequential to make the math easier: https://community.powerbi.com/t5/Quick-Measures-Gallery/Sequential/m-p/380231

[po]

Thanks for reply ande useful linkss.

Finding the fromula below works when have a slicer aqnd selecting a week will calculate the value relative to that previous week but issue have is if want to say have a few weeks showing at once below will only show one value as the max of the latest date shown is used.

e.g if 201904 will show 201903 but 201902 and 201901 will be blank. 

calculate(SUMX(sales,sales[amount sold]) ,filter(all
(calendar),calendar[Date]=MAX(calendar[Date])-7) )

[Greg_Deckler · Accepted solution]

I think you want:

Measure = 
VAR __max = MAX(calendar[Date])
RETURN
calculate(SUMX(sales,sales[amount sold]) ,filter(all
(calendar),calendar[Date]=__max-7) )

If you have the week in the visual and this, then the first line should be context constrained to the row.

[po]

Thansk - yes this is what I thought.  However, when do this if have say weeks 201901 to 201904 see that the row with 201903  is populated (as has max date-7) assuming in week 201904 but other rows are blank for previous week value.

[po]

Looks to be working now not sure why wasn't before