previousmonth multiple values error

[Broly221]

I have a Date table and I'm trying to display the previous month date for each dates. When I display the previousday it works fine :

Problem is when I try to display the previous month instead of the previousday it gives me a multiple value error : 

I don't really understand why it doesnt work for the previous month. How can I get the previous month sales without having this "multiple values" error ?

Thank you for your help

[Broly221]

Thanks for your answer,

When I try ; calculate( [Quantity], Previousmonth( 'Date'[Date] )

I gives the same error. How come ? why does it work with previousday() but not previousmont() ? 

[Greg_Deckler]

@Broly221 That's not how PREVIOUSMONTH works, PREVIOUSMONTH is intended to be used in conjunction with a CALCULATE statement. Try this instead:

Better Year to Date Total - Microsoft Power BI Community

You may find this helpful - https://community.powerbi.com/t5/Community-Blog/To-bleep-With-Time-Intelligence/ba-p/1260000

Also, see if my Time Intelligence the Hard Way provides a different way of accomplishing what you are going for.

https://community.powerbi.com/t5/Quick-Measures-Gallery/Time-Intelligence-quot-The-Hard-Way-quot-TIT...