Power BI :: why SWITCH doesn't allows me to select columns?

Question

I have created a dashboard with a SWITCH that can allows me to change one table column from USD to CHF.

• .PBIX
• .CSV

the goal was to try to avoid Bookmarks which I hate.

But I don't like the solution because I had to create 2 useless metrics:

• Cost_in_Dollars = SUM('Currency'[costInPricingCurrency])
• Cost_in_Francs = SUM('Currency'[costInBillingCurrency])

These ae just metrics that reproduce the exact same columns for no reason!

And after that I was able to create the Switch:

Selected Name = 
SWITCH (
    SELECTEDVALUE ( Option[Name] ),
    "Dollars", [Cost_in_Dollars],
    "Francs", [Cost_in_Francs])

This because the switch wouldn't allow me to use the columns [costInPricingCurrency] and [costInBillingCurrency] directly.

Why in the hell the switch doesn't work if I use:

Selected Name = 
SWITCH (
    SELECTEDVALUE ( Option[Name] ),
    "Dollars", [costInPricingCurrency],
    "Francs", [costInBillingCurrency])

So the code is overall working.

I just want to understand why do I have to create a metrics instead of using the column directly.

I find this very stupid.

Can you explain, please?

Answer 1

In DAX, IF and SWITCH can only return a scalar value, they can't return tables or columns.

You could change it to:

Selected Name = 
  SWITCH (
    SELECTEDVALUE ( Option[Name] ),
    "Dollars", SUM('Currency'[costInPricingCurrency]),
    "Francs", SUM('Currency'[costInBillingCurrency])
  )