DAX Percent Change Versus Date Specified?

[joeshu26]

If I have a simple measure Total Sales:=SUM(fact[Sales]) what would be best way to calculate percent change from a specified date?

For example if I select 1/15/2014 from a slicer or filter, the measure would calculate percent change of Total Sales for the filter context versus 1/15/2014?

 

[Matt Allington]

assuming you have a standard Gregorian calendar (ie not an ISO or 445 calendar) then you can simply use SAMEPERIODLASTYEAR to fetch the numbers from the prior year.

Last Year Sales =CALCULATE([Total Sales],SAMEPERIODLASTYEAR(Calendar[date]))

From there you can work out the percent