Calculating days between Finish Time to Finish Time

[bhattg]

Hello,

I have the following data and trying to calculate days between Finish Dates, the desired output is highlighted in yellow in the second pic below:     

First Pic: Data Layout

        Data Layout

Second Pic: Desired output

I need help with writing a DAX expression that would calculated date difference between each row sequentially.

[johnyip]

Hi @bhattg ,

I observed that the [FINISH DATE] in your sample data is "sorted naturally" ascendingly. Please try using this DAX, it involves using the window function that PowerBI has introduced recently, which also takes me some time to practice:

Days Between = 
VAR Data = 
PATHITEM(CONCATENATEX(OFFSET(1,ORDERBY('Table (2)'[FINISH DATE],ASC)),[FINISH DATE],"|"),1)
VAR Is_Blank = Data=BLANK()
RETURN IF(Is_Blank,"NULL",ABS(VALUE(VALUE(Data)-MAX('Table (2)'[FINISH DATE]))))

VERY IMPORTANTLY, please ensure your table vis has sorted [FINISH DATE] correctly (ascendingly as per [FINISH DATE]) as shown, unless you don't mind at all about the display order.

For an alternative DAX, inspired by your reply, you can use DATEDIFF() instead of my verison, which is:

Days Between = 
VAR Data = 
PATHITEM(CONCATENATEX(OFFSET(1,ORDERBY('Table (2)'[FINISH DATE],ASC)),[FINISH DATE],"|"),1)
VAR Is_Blank = Data=BLANK()
RETURN IF(Is_Blank,"NULL", ABS(DATEDIFF(VALUE(Data),MAX('Table (2)'[FINISH DATE]),DAY)))

If your actual data's [FINSIH DATE] is not "sorted naturally", I think you should include a [ROW NUMBER] column in your dataset, created either by SQL selection or other means you used, and then use that [ROW NUMBER] column in your DAX, like the following (you also need to include that [ROW NUMBER] column in your table vis, sorted ascendingly. you can adjust the width of that column to 0 for formatting):

Days Between = 
VAR Data = 
PATHITEM(CONCATENATEX(OFFSET(1,ORDERBY('Table (2)'[ROW NUMBER],ASC)),[FINISH DATE],"|"),1)
VAR Is_Blank = Data=BLANK()
RETURN IF(Is_Blank,"NULL", [use your own preferred version of calculation here, see above])

[johnyip]

hi @bhattg , does this answer your question? If so, kindly accept it as a solution so others facing similar issuescan look for this thread.

[johnyip]

Hi @bhattg , can I know how to determine the start date / time? Without that info, it is hard to assist.

[bhattg]

I was trying the following expression but this calculates days between Min and Max date (2 parents), does not work with more than 2 Parents. Saw this on another post.

Measure = 
VAR MAX_Date =
    CALCULATE (
        MAX ( Table1[Finishdate] ),
        ALLEXCEPT(Table1,Table1[Parent])
    )
VAR MIN_Date =
    CALCULATE (
        MIN( Table1[FinishDate] ),
        ALLEXCEPT(Table1,Table1[Parent])
    )
RETURN
    DATEDIFF ( MIN_Date,MAX_Date, DAY )

[johnyip]

Yes, by this DAX it obviously calculates the difference between the largest and smallest date within your data, which is not you wish to calculate.

[bhattg]

Days Diff will start for each Parent with Type X, therefore, for the first Parent (112233) and its four Children, start date will be determined by Type "X".

I hope i answered your question.