Forum Discussion

SuddenClarity's avatar
SuddenClarity
Helper I
3 years ago
Solved

SAMEPERIODLASTYEAR doesn't work as a variable

I tried to write the following:   Sales YoY = VAR CY = [Total Sales] VAR PY = CALCULATE(CY, SAMEPERIODLASTYEAR('Calendar'[Date])) RETURN IF ( ISBLANK (PY), BLANK(), CY - PY  )   But it r...
  • FreemanZ's avatar
    FreemanZ
    3 years ago

    hi SuddenClarity 

    the issue is from the nature of variable in DAX. Once defined, a variable is stored as a constant. So whatever filter you add in expressions like

    CALCULATE(CY, SAMEPERIODLASTYEAR('Calendar'[Date]))

    it simply return CY, a constant defined before. 

    So CALCULATE([Total Sales], SAMEPERIODLASTYEAR('Calendar'[Date])) is the right approach.

FreemanZ's avatar
FreemanZ
Super User
3 years ago

hi SuddenClarity 

the issue is from the nature of variable in DAX. Once defined, a variable is stored as a constant. So whatever filter you add in expressions like

CALCULATE(CY, SAMEPERIODLASTYEAR('Calendar'[Date]))

it simply return CY, a constant defined before. 

So CALCULATE([Total Sales], SAMEPERIODLASTYEAR('Calendar'[Date])) is the right approach.