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Wickin's avatar
Wickin
Frequent Visitor
8 years ago
Solved

Calculate difference between two rows by using Index column

Hi al,   I know this question has been asked before, but I tried them all and wasn't able to compete. Sorry!   I've got the below table (4 colums) within Power BI (just created a table in Excel t...
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  • Stachu's avatar
    Stachu
    8 years ago

    try this

    Column =
VAR Index = 'Table'[Index]
VAR Reference = 'Table'[Reference]
VAR PrevKilometers =
    CALCULATE (
        FIRSTNONBLANK ( 'Table'[Kilometers], TRUE () ),
        FILTER ( 'Table', 'Table'[Index] = Index - 1 && 'Table'[Reference] = Reference )
    )
RETURN
    IF (
        ISBLANK ( PrevKilometers ),
        BLANK (),
        'Table'[Kilometers] - PrevKilometers
    )
Anonymous's avatar
Anonymous
Not applicable
6 years ago

How can I adjust your formula to include data also as a criteria ?

i.e.,compare the values between current timestamp and previous time stamp,say 17-08-2019,10:25 P.M and 17-08-2019,10:30 P.M.

I have an ID Field and the glucose values,I should be capable of comparing the glucose_value,every now and then to indicate the episodes or spike in glucose level.

Thanks

Stachu 

Stachu's avatar
Stachu
Community Champion
6 years ago

the ID can be the same for multiple dates?
if yes then the difference in glucose for a given ID should be something like this:

Column =
VAR __ID = 'Table'[ID]
VAR __DateTime = 'Table'[DateTime]
VAR __PreviousDateTime =
    CALCULATE (
        MAX ( 'Table'[DateTime] ),
        FILTER ( 'Table', 'Table'[ID] = __ID && 'Table'[DateTime] < __DateTime)
    )
VAR __PreviousGlucose = 
    CALCULATE (
        MAX ( 'Table'[Glucose] ),
        FILTER ( 'Table', 'Table'[ID] = __ID && 'Table'[DateTime] = __PreviousDateTime)
    )
RETURN
    IF (
        ISBLANK ( __PreviousDateTime ),
        BLANK (),
        'Table'[Glucose] - __PreviousGlucose
    )