Start Date of the same week number previous year

[BlueDaisy]

Hello,

Could you please help me in writting a DAX measure for the calculation of the difference (days) between the start of the this week and the start of the same week NUMBER previous year)? I have a weekly calendar table as shown:

I cannot use SAMEPERIODLASTYEAR because the week does not start on the same day. With the small modification of the formula, I get what I need, but 1 day of adjustmet is hardcoded (i am trying to make it dynamic). Thanks.

My Dax is not working as expected.

[BlueDaisy]

it worked. Thank you!!!

[Anonymous · Accepted solution]

Hi @BlueDaisy ,

Please update the formula of your measure [TestTest] as below and check if it can return your expected result.

TestTest =
VAR _curdate =
    SELECTEDVALUE ( dim_week[WeekStart] )
VAR _year =
    YEAR ( _curdate )
VAR _week =
    WEEKNUM ( _curdate, 2 )
VAR _pywsday =
    CALCULATE (
        MIN ( dim_week[WeekStart] ),
        FILTER (
            ALL ( dim_week ),
            dim_week[WeekStart]
                >= DATE ( _year - 1, 1, 1 )
                && dim_week[WeekStart]
                    <= DATE ( _year - 1, 12, 31 )
                && WEEKNUM ( dim_week[WeekStart], 2 ) = _week
        )
    )
RETURN
    DATEDIFF ( _pywsday, _curdate, DAY )

If the above one can't help you, please provide more raw data in your tables (exclude sensitive data) with Text format and your expected result with backend logic and special examples. It would be helpful to find out the solution. You can refer the following links to share the required info:

How to provide sample data in the Power BI Forum

And It is better if you can share a simplified pbix file. You can refer the following link to upload the file to the community. Thank you.

How to upload PBI in Community

Best Regards