Dynamic Grouping in Power BI using DAX

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It has been quite a while since I posted something and was already thinking of dusting up my tools. That was when I was going through the Power BI Community forums, and found an interesting question –

Requirement: The user wants a report with a column chart. The X axis will have Subcategory Name and the value will be the sum of Internet Sales. Along with this chart, the user will have a slicer where they can select the Subcategory Names. The column chart should “update” showing one column for each selected subcategory, and another column named “Others” with the summed amount of the rest of the unselected categories.

Basically, they wanted a dynamic group called “Others” and the members within this group should change based on what is selected on the slicer.

This would be a good time to show a visual representation of what the requirement means.

You can see that there is one individual (green) column for every selected Subcategory and also one (orange/red) column called “Other” which has the summed up value for the rest of the unselected categories.

For solving this, follow the steps below:-

1) The “Other” member is not available in any existing column. So we will have to create a new table having a column for all the subcategories, as well as an additional member for Others. For this, I made a new calculated table in Power BI using the formula below

ProdSubCat_List =
UNION (
    — get the existing values of subcategory name   
    VALUES ( ProductSubcategory[Product Subcategory Name] ),
    — add the other member
    ROW ( “SubCategoryName”, “Other” )
)

The Subcategory column from this table has to be used in the charts, since this is the only column which has the “Other” member. At the same time, this table is a disconnected table (which means that there is no relationship between this table and the rest of the fact/dimension tables), so we will not get any proper values if we just use the Sales measure with this column in a column chart. For that, we will have to create a custom measure.

2) The next step is to make a measure which will display the values

NewSalesMeasure =
VAR SelectedSales =
    CALCULATE (
        [Sales Amount],
        INTERSECT (
            VALUES ( ProductSubcategory[Product Subcategory Name] ),
            VALUES ( ProdSubCat_List[Product Subcategory Name] )
        )
    )
VAR UnSelectedSales =
    CALCULATE (
        [Sales Amount],
        EXCEPT (
            ALL ( ProductSubcategory[Product Subcategory Name] ),
            VALUES ( ProductSubcategory[Product Subcategory Name] )
        )
    )
VAR AllSales =
    CALCULATE (
        [Sales Amount],
        ALL ( ‘ProductSubcategory'[Product Subcategory Name] )
    )
RETURN
    IF (
        HASONEVALUE ( ProdSubCat_List[Product Subcategory Name] ),
        SWITCH (
            VALUES ( ProdSubCat_List[Product Subcategory Name] ),
            “Other”, UnSelectedSales,
            SelectedSales
        ),
        AllSales
    )

Note that we are making use of 3 variables – SelectedSales, UnSelectedSales and AllSales to handle the 3 conditions that can arise.

SelectedSales will match the member values in the our calculated table (ProdSubCat_List) with the Subcategory names in the original Subcategory table and get their corresponding Sales Amount.

UnSelectedSales will get the Sales Amount for all the unselected Subcategory names, and we make use of the EXCEPT function for this.

AllSales is the total Sales Amount for all the Subcategories, and is used for showing the grand total.

3) Create a column chart with ProdSubCat_List[Product Subcategory Name] on axis and NewSalesMeasure on values. Put a slicer which has ProductSubcategory[Product Subcategory Name]. Now you can see the required end result.