Calculate the difference in values between previous dates

[Uka]

Hello,

Please can you help me to return the difference between two values within some given dates as below;

So, I would like to substract the previous date value from the current one ie ((Eng FullTime) on the 13/10/2023) - ((Eng FullTime) on the 06/10/2023)

The (Eng Fulltime) is a measure that was calclulated as below; 

Eng FullTime = CALCULATE(DISTINCTCOUNT('ENG SOB'[Employee]), FILTER('ENG SOB', 'ENG SOB'[Groups] = "Engineer"))

Many thanks in advance!

[Greg_Deckler]

@Uka See my article on Mean Time Between Failure (MTBF) which uses EARLIER: http://community.powerbi.com/t5/Community-Blog/Mean-Time-Between-Failure-MTBF-and-Power-BI/ba-p/3395....
The basic pattern is:
Column = 
  VAR __Current = [Value]
  VAR __PreviousDate = MAXX(FILTER('Table','Table'[Date] < EARLIER('Table'[Date])),[Date])

  VAR __Previous = MAXX(FILTER('Table',[Date]=__PreviousDate),[Value])
RETURN
  __Current - __Previous

[Uka]

Hello @Greg_Deckler ,

The solution did not work for me as I got a wired result as below;

Below is the code that I used;

#Result =

  VAR __Current = CALCULATE(DISTINCTCOUNT('ENG SOB'[Employee]), FILTER('ENG SOB', 'ENG SOB'[Groups] = "Engineer"))

  VAR __PreviousDate = MAXX(FILTER('ENG SOB','ENG SOB'[Operational Date] < EARLIER('ENG SOB'[Operational Date])),[Operational Date])

  VAR __Previous = MAXX(FILTER('ENG SOB',[Operational Date]=__PreviousDate),[Eng FullTime])

RETURN

  __Current - __PreviousDate

@Greg_Deckler Please can you offer another method?

[Greg_Deckler]

@Uka Post your sample data as text/table and I'll take a look.

[Uka · Accepted solution]

Hi @Greg_Deckler ,

Many thanks for your assistance!

I have now figured it out using the following;

Weekly Difference =

Var _selecteddate = VALUES('Date Friday Only'[Date])

var _maxdate = MAXX(_selecteddate, 'Date Friday Only'[Date])

var _value2 = CALCULATE([Eng FullTime], 'Date Friday Only'[Date] = _maxdate)

var _value3 = CALCULATE([Eng FullTime], 'Date Friday Only'[Date] = _maxdate -7)

Return

_value2 - _value3

_value3 has -7 because the dates occur every 7 days, thus returns the date for the previous week

Thanks

[Greg_Deckler]

@Uka That works!