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fabo's avatar
fabo
Advocate III
9 years ago
Solved

Conditional Top 20

Hi everyone.    I have this scenario: 219 plants ("Production Unit" or "PU") are located in 15 geographical regions. They produce only one product in different amounts. Data is collected monthly. V...
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  • Vvelarde's avatar
    Vvelarde
    9 years ago

    fabo

     

    Hi, Please try with this measure:

     

    ProductionShow =
IF (
    HASONEVALUE ( T_Region[Region] ),
    [Sum of Production],
    IF (
        COUNTROWS (
            INTERSECT (
                VALUES ( T_PU[Production Unit] ),
                TOPN ( 20, ALLSELECTED ( T_PU[Production Unit] ), [Sum of Production], DESC )
            )
        )
            > 0,
        [Sum of Production],
        BLANK ()
    )
)

     

    Regards

     

    Victor

    Lima - Peru

Vvelarde's avatar
Vvelarde
Community Champion
9 years ago

Anonymous

 

Hi, the dax code work very simple:

 

1. When a Region is selected show the productions unit to belong to The Regions Selected.

 

2. When None Region is selected. (This could be read like "All" the regions is selected)

 

Take The value of the Production Unit (Values) (One by One)

 

And another Table with The Top 20 of All Selected PUnits. (of All the Regions selected)

 

I Use The Intersect to evaluate if The Production Unit is included in the Top 20. When the Rows in the Intersect (Table) is greater than 0 means that this PUnit is in the Top 20 so calculate the Sum of Production. If is 0 then Blank(To don't show in the visual)

 

For every Production Unit repeat this evaluation.

 

 

ProductionShow =
IF (
    HASONEVALUE ( T_Region[Region] ),
    [Sum of Production],
    IF (
        COUNTROWS (
            INTERSECT (
                VALUES ( T_PU[Production Unit] ),
                TOPN ( 20, ALLSELECTED ( T_PU[Production Unit] ), [Sum of Production], DESC )
            )
        )
            > 0,
        [Sum of Production],
        BLANK ()
    )
)

 

I hope this will be guide to understand the code.

 

Regards

 

Victor

Lima - Peru

 

Anonymous's avatar
Anonymous
Not applicable
9 years ago

Victor, 

I see the logic now. You are comparing one by one the values of all production units with TOP 20 production units.  So, this is an iteration process if you are going one by one.  To my knowledge, neither COUNTROWS nor INTERSECT are the iterators. How is this iteration achieved? 

 

Tks

 

  • Vvelarde's avatar
    Vvelarde
    Community Champion
    9 years ago

    Anonymous

     

    Is not an iterator.

     

    The evaluation (one by one) is "created/Applied" by the visual. 

     

    Everytime that the visual is charting each Production Unit calculate the Dax Code (measure)

     

    So when is 0 the result is blank don't put in the visual .

     

     

     

     

     

    • Anonymous's avatar
      Anonymous
      Not applicable
      9 years ago

      Victor, 
      Thanks for the clarifications. However, one thing remains little fuzzy. 

       

      Let's drop the HASONEVALUE() part since its functionality here is clear and focus on the inner IF()

       

       

      You DAX logic basically says : ( if converted to some pseudo-DAX code )

       

      IF( 
          COUNTROWS ( <Top 20 Logic>) > 0,
          [Sum of Production],
          BLANK ()
         )

       

      How are you getting COUNTROWS ( <Top 20 Logic>) > 0  to march with the [Production Unit] 


      Could you please be so kind to elaborate a little more on your words here : "When the Rows in the INTERSECT (Table) is greater than 0 this means that this [Production Unit] is in the Top 20"

      Thanks

       

      • Vvelarde's avatar
        Vvelarde
        Community Champion
        9 years ago

        Anonymous

         

        I try to explain without dax.

         

        The logic behind this is:

         

        If the ProductionUnit is in the list of Top 20 Product Units show the Total of Production of this PUnit.  Is not in the list don't show (Blank).

         

        How obtain this:

         

        Combining Countrows and Intersect.

         

        The result of Intersect is a table with the Intersection of Production Unit  and the Top 20 Production Units. In this scenario 1 Row is in the Top 20 and 0 rows if not.

         

        Finally with the IF --Countrows count the rows in the Intersect Table. If Countrows give me a 0 don't show (blank) everything else show the Production Sum. 

         

        So this steps Power BI repeat to every ProductionUnit in the moment that is creating (Drawing) the visual.