Dynamic Top N Product Sales Analysis

You can indeed create a measure to analyze your data based on the top N products. However, the SWITCH function is generally used for situation where you need to evaluate an expression against a list of values. For this scenario, simple modifications to your previous DAX measures would suffice.

To have a TopN dynamic ranking, you'd need to create a slicer where you can select the number N for your 'Top N Products'. Create a table in Power BI:

TopNTable = 
DATATABLE("TopN",Integer, {{1},{2},{3},{4},{5},{6},{7},{8},{9},{10}})

Now, you can create a slicer from this table and always select a single value.

To implement this in your DAX code, you will need to create a measure that combine RANKX function which enables you to rank the total sales of each product and ALL function to remove any filters on the Products table. Then, filter this rank according to the selected value in the slicer.

DynamicTopNProductSales = 
Summarize(Products, 'Product'[Product Name], "Sales", 
CALCULATE(SUM('Sales'[Sales])),
"Rank", RANKX(ALL('Product'[Product Name]), [Sales],,DESC,Dense)
)

This will create a new table, sorting products by sales in descending order and providing a rank for each product.

TopNProductSales =
CALCULATE(SUM('Sales'[Sales]), 
FILTER('Product', [DynamicTopNProductSales] <= SELECTEDVALUE('TopNTable'[TopN])))

This will give you the total sales for the 'Top N' products you selected in your slicer with N ranging from 1 to 10. Adjust the range in the 'TopNTable' as you see fit. If no value is selected in the slicer, it will show the total sales for all products.

This setup provides the advantage of real-time filtering of top N product sales. It is completely dynamic and interactive enabling in-depth data analysis. You can easily change the number of Top N products you want to display by simply selecting different values from the slicer.