last week

Anonymous , Please refer to this file, I have used week rank to get this week, last week rolling week. Typically same weekday is 7 days behind.

7 Days behind Sales = CALCULATE(SUM(Sales[Sales Amount]),dateadd('Date'[Date],-7,Day))

The above is one method. Check this file: https://www.dropbox.com/s/d9898a48e76wmvl/sales_analytics_weekWise.pbix?dl=0

Hi Anonymous , 

I am not clear  about your requirement, if you want to create a column to define weekname, you could try below M code

let
    Source = List.Dates(#date(2020,4,1), 30, #duration(1,0,0,0)),
    #"Converted to Table" = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Added Custom" = Table.AddColumn(#"Converted to Table", "Custom", each if Date.IsInCurrentWeek([Column1]) then "current week" else if Date.IsInPreviousNWeeks([Column1], 1) then "last 1 week"  else if Date.IsInPreviousNWeeks([Column1], 2)  then "last 2 week"  else null)
in
    #"Added Custom"

If this is not what you want, could you please inform me more detailed information(such as your expected output and your sample data (by OneDrive for Business))? Then I will help you more correctly.

Please do mask sensitive data before uploading.

Thanks for your understanding and support.
Best Regards,
Zoe Zhi

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

This is what I used