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greenawayr's avatar
greenawayr
Helper I
6 years ago
Solved

Variance between rows if multiple entries exist in specified timeframe

Hi,   Fairly new to PowerBI here so sorry if this is something that should be straightforward.   I have a parent table that has Unique ID for each row.   I have a child table that gets written ...
Need Help
  • Anonymous's avatar
    Anonymous
    6 years ago

    Hi greenawayr,

    In fact, I already filter on the 'parent' field to find out the minimum date based on its 'id' and stored into a variable.
    After these steps, you can use current id and the first date to lookup the correspond score and calculate with the current score to get the diff.

    Diff =
VAR currScore =
    MAX ( LIVE[Score] )
VAR currID =
    MAX ( LIVE[ID] )
VAR currDate =
    MAX ( LIVE[Modified] )
VAR prevDate =
    CALCULATE (
        MIN ( Staging[Modified] ),
        FILTER (
            ALLSELECTED ( Staging ),
            [ParentID] = currID
                && [Modified] <= currDate - 30
        )
    )
VAR prevScore =
    LOOKUPVALUE (
        Staging[Score],
        Staging[ParentID], currID,
        Staging[Modified], prevDate
    )
RETURN
    IF ( prevDate <> BLANK (), currScore - prevScore, 0 )

    BTW, My formula is a measure, please not use it in a calculated column.

    Regards,

    Xiaoxin Sheng

Anonymous's avatar
Anonymous
Not applicable
6 years ago

HI greenawayr ,

I'd like to suggest you use parent key id to lookup related detail records, then you can do variance calculation by VARX.P VARX.S functions. BTW, can you please share the parent table structure to help us clarify your requirement for test? 

How to Get Your Question Answered Quickly 
Regards,

Xiaoxin Sheng

greenawayr's avatar
greenawayr
Helper I
6 years ago

Thanks,

 

So I'm dealing with a "LIVE" table and a "Staging" table. So the schemas are much the same, but the live table only holds one row per record and the staging table holds a record for each modifcation made to the parent record.

 

So LIVE

IDMODIFIEDScore
101/22/202015
201/22/20208
301/20/202012

 

and Staging

RowIDParentIDModifiedScore
6201/22/20208
5101/22/202015
4301/20/202012
3201/10/202012
2212/20/201911
1112/05/201913

 

So for the LIVE table, ID 2, it's current score is 8, but 30 days ago it was 11 (we ignore the score change that made it 12, we just want the score as it was 30 days ago) and the variance is -3.

 

Hope this helps. Thanks

  • Anonymous's avatar
    Anonymous
    Not applicable
    6 years ago

    Hi greenawayr,

    You can try to use the following measure formula to get the diff between the current 'live' score and filtered first 'staging' score based on 'ID' group:

    Diff =
VAR currScore =
    MAX ( LIVE[Score] )
VAR currID =
    MAX ( LIVE[ID] )
VAR currDate =
    MAX ( LIVE[Modified] )
VAR prevDate =
    CALCULATE (
        MIN ( Staging[Modified] ),
        FILTER ( ALLSELECTED ( Staging ), [ParentID] = currID )
    )
VAR prevScore =
    LOOKUPVALUE (
        Staging[Score],
        Staging[ParentID], currID,
        Staging[Modified], prevDate
    )
RETURN
    currScore - prevScore

    Regards,

    Xiaoxin Sheng

    • greenawayr's avatar
      greenawayr
      Helper I
      6 years ago

      Sorry, I'm not having much luck with this, I may not be explaining it properly.

       

      My Staging table could contain multiple rows child rows and therefore I need a way to return the current score, only for the first row that matches my Parent ID, is older than 30 days and sorted in ascending order.

       

      I've created a column that calculates the number of days between todays date and the modified date, and gives me an integer, so in theory I'm looking for the score where ID = Parent and && CalculatedModifiedDate > 30. However, because this returns more than one value, I'm getting errors around returning multiple results in a scalar value. I've TopN, Min etc, but keep seeming to get the same error.

       

      How do I get only one result returned so I can store that in a column and subtract it from my LIVE score?

      Thanks for your help so far.

      • Anonymous's avatar
        Anonymous
        Not applicable
        6 years ago

        Hi greenawayr,

        In fact, I already filter on the 'parent' field to find out the minimum date based on its 'id' and stored into a variable.
        After these steps, you can use current id and the first date to lookup the correspond score and calculate with the current score to get the diff.

        Diff =
VAR currScore =
    MAX ( LIVE[Score] )
VAR currID =
    MAX ( LIVE[ID] )
VAR currDate =
    MAX ( LIVE[Modified] )
VAR prevDate =
    CALCULATE (
        MIN ( Staging[Modified] ),
        FILTER (
            ALLSELECTED ( Staging ),
            [ParentID] = currID
                && [Modified] <= currDate - 30
        )
    )
VAR prevScore =
    LOOKUPVALUE (
        Staging[Score],
        Staging[ParentID], currID,
        Staging[Modified], prevDate
    )
RETURN
    IF ( prevDate <> BLANK (), currScore - prevScore, 0 )

        BTW, My formula is a measure, please not use it in a calculated column.

        Regards,

        Xiaoxin Sheng