Forum Discussion

Anonymous's avatar
Anonymous
Not applicable
3 years ago
Solved

Getting Previous Row using DAX measure

Hello all,  I need to get previous record based on DateTime column and grouped by TagIndex column   I created this measure,   Prev_value_Energy_consum = VAR Index = [Index] VAR Prev_date =...
Jihwan_Kim's avatar
Jihwan_Kim
Super User
3 years ago

Hi,

Thank you for your sharing.

Could you please try the below if it works?

 

Prev_value_Energy_consum =
VAR Index = [Index]
VAR Prev_datetime =
    MAXX (
        FILTER (
            ALLSELECTED ( FloatTable ),
            FloatTable[Date] = SELECTEDVALUE ( FloatTable[Date] )
                && FloatTable[Time] < SELECTEDVALUE ( FloatTable[Time] )
        ),
        FloatTable[Time]
    )
VAR Prev_date =
    MAXX (
        FILTER (
            ALLSELECTED ( FloatTable ),
            FloatTable[Date] < SELECTEDVALUE ( FloatTable[Date] )
        ),
        FloatTable[Date]
    )
VAR Prev_time =
    MAXX (
        FILTER ( ALLSELECTED ( FloatTable ), FloatTable[Date] = Prev_date ),
        FloatTable[Time]
    )
RETURN
    SWITCH (
        TRUE (),
        NOT ISBLANK ( Prev_datetime ),
            CALCULATE (
                SUMX ( FloatTable, VAR Index = FloatTable[TagIndex] RETURN FloatTable[Val] ),
                FILTER (
                    ALLSELECTED ( FloatTable ),
                    FloatTable[Time] = Prev_datetime
                        && FloatTable[Date] = SELECTEDVALUE ( FloatTable[Date] )
                        && FloatTable[TagIndex] = Index
                )
            ),
        CALCULATE (
            SUMX ( FloatTable, VAR Index = FloatTable[TagIndex] RETURN FloatTable[Val] ),
            FILTER (
                ALLSELECTED ( FloatTable ),
                FloatTable[Time] = Prev_time
                    && FloatTable[Date] = Prev_date
                    && FloatTable[TagIndex] = Index
            )
        )
    )
Anonymous's avatar
Anonymous
Not applicable
3 years ago

Hi Jihwan_Kim 

Thankyou so much measure is working correct,

but there is still one small issue remaining when I am trying to subtract the value from previous value using calculated column, then It is working fine but at same point of time when time difference b/w 2 consecutive rows is greater than 10 minutes it is showing same value rather than subtracting.
I think this could beacuse we've used switch function in the measure and calculted column is confused which value to take, I may not correct I am just thinking out loud.
 

 

Here is the sample file for the same : https://drive.google.com/drive/folders/1651tuMrez13NX48mrdh_UVSZuk7diGMP?usp=sharing

Thanks and Regards
Mihir

 

  • Jihwan_Kim's avatar
    Jihwan_Kim
    Super User
    3 years ago

    Hi,

    Could you please try writing a measure like below, instead of creating Calcualted Column?

     

    Test measure: = 
SUM(FloatTable[Val]) - [Prev_value_Energy_consum]
    • Anonymous's avatar
      Anonymous
      Not applicable
      3 years ago

      Hi Jihwan_Kim 
      Yeah It is working in measure, but I am prefering calculated column beacuse I need Sum of this and in measure it is giving incorrect value, or I am not sure to fix it in measure..
      Can you help me with calculated column or measure which would aggregate same value as in calculated column?

      Thanks and Regards
      Mihir

      • Jihwan_Kim's avatar
        Jihwan_Kim
        Super User
        3 years ago

        Hi,

        Please check the below DAX formula for creating a calcualted column.

        It will take quite a long time to load the newly created column, but I could not optimize it for now. (On my computer, it took more than 3 mintues to load a calcualted column).

        My suggestion is still creating a measure to show the same result.

        Thanks.

         

        Energy_consum CC =
VAR _configtable =
    FILTER ( FloatTable, FloatTable[TagIndex] = EARLIER ( FloatTable[TagIndex] ) )
VAR Prev_datetime =
    MAXX (
        FILTER (
            _configtable,
            FloatTable[Date] = EARLIER ( FloatTable[Date] )
                && FloatTable[Time] < EARLIER ( FloatTable[Time] )
        ),
        FloatTable[Time]
    )
VAR Prev_date =
    MAXX (
        FILTER ( _configtable, FloatTable[Date] < EARLIER ( FloatTable[Date] ) ),
        FloatTable[Date]
    )
VAR Prev_time =
    MAXX ( FILTER ( _configtable, FloatTable[Date] = Prev_date ), FloatTable[Time] )
RETURN
    FloatTable[Val]
        - SWITCH (
            TRUE (),
            NOT ISBLANK ( Prev_datetime ),
                MAXX (
                    FILTER (
                        _configtable,
                        FloatTable[Time] = Prev_datetime
                            && FloatTable[Date] = EARLIER ( FloatTable[Date] )
                    ),
                    FloatTable[Val]
                ),
            MAXX (
                FILTER (
                    _configtable,
                    FloatTable[Time] = Prev_time
                        && FloatTable[Date] = Prev_date
                ),
                FloatTable[Val]
            )
        )