I am figuring out to calculate Weekly YOY Sales %age in tableau. Here in the attached workbook (10.5 version) user has the option to select any week end date. So for any selected week, I should be able to compare with same week number of last year and calculate %age growth/ deficit. For Eg for the selected week 9/8/2018,Sales is 532702. The week number of the selected week here is 36. So for last year 2017 week no. 36 Sales is 399527. So the YOY calculation will be ( CY WeekEnd Sales - LY Weekend Sales) / LY Weekend Sales. This will be (532702 - 399527) / 399527 = 33.33% . This value needs to populate in the YOY Growth space given in the below screenshot.
I have just mocked up this data for keeping it simple. My challenge is here is to get this YOY % value without using any date parameter here. Any help to get this value without using the date Parameter would be highly appreciated.