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MaggieWang
Frequent Visitor

COVID-19 US Tracking Sample - DAX Formula for Daily Death measure

Hi, I am practicing writing DAX formulas and come across the following measure from the "COVID-19 US Tracking Sample" file.

      Daily deaths =
      VAR __CountyName = 'COVID'[County Name]
      VAR __State = 'COVID'[State]
      VAR __Yesterday =  DATEADD(COVID[Date],-1,DAY)
      VAR __TodaysDeaths = 'COVID'[Deaths]
      RETURN  __TodaysDeaths - CALCULATE(
          SUM('COVID'[Deaths]) ,
          FILTER(
              COVID,
              COVID[Date] = __Yesterday &&
              COVID[County Name] = __CountyName &&
              COVID[State] = __State
          )
      ) + 0
Everything makes perfect sense except the last "+ 0" part. Why was the + 0 required at the end of the measure, was it for providing an initial value for doing the SUM? Many thanks.
1 ACCEPTED SOLUTION
CNENFRNL
Super User
Super User

Hi, @MaggieWang , it's a common trick to convert BLANK() to 0, i.e. when this part of measure

 

__TodaysDeaths - CALCULATE(
          SUM('COVID'[Deaths]) ,
          FILTER(
              COVID,
              COVID[Date] = __Yesterday &&
              COVID[County Name] = __CountyName &&
              COVID[State] = __State
          )
      )

 

returns BLANK(), it can be converted to 0.

Try this measure to see the affect

Test = BLANK() + 0

Thanks to the great efforts by MS engineers to simplify syntax of DAX! Most beginners are SUCCESSFULLY MISLED to think that they could easily master DAX; but it turns out that the intricacy of the most frequently used RANKX() is beyond their comprehension!

DAX is simple, but NOT EASY!

View solution in original post

2 REPLIES 2
Anonymous
Not applicable

If you remove +0, you'll see immediately why it's there. And no, it's not necessary unless you want to see 0 instead of BLANK...
CNENFRNL
Super User
Super User

Hi, @MaggieWang , it's a common trick to convert BLANK() to 0, i.e. when this part of measure

 

__TodaysDeaths - CALCULATE(
          SUM('COVID'[Deaths]) ,
          FILTER(
              COVID,
              COVID[Date] = __Yesterday &&
              COVID[County Name] = __CountyName &&
              COVID[State] = __State
          )
      )

 

returns BLANK(), it can be converted to 0.

Try this measure to see the affect

Test = BLANK() + 0

Thanks to the great efforts by MS engineers to simplify syntax of DAX! Most beginners are SUCCESSFULLY MISLED to think that they could easily master DAX; but it turns out that the intricacy of the most frequently used RANKX() is beyond their comprehension!

DAX is simple, but NOT EASY!

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