periodOverPeriodDifference function not giving values

[ErikG]

HI @kanzhao
please have a look at

Creating period comparisons with QuickSight's periodOver and periodTo functions

This article uses the SaaS-Sales Dataset that you can download as part of the QuickSight Author Workshop. We will update the data to the current date so your calculations are realistic. If you do not have a QuickSight account please follow the instructions in the Initial Setup. Instructions to create the dataset can be found in Exercise 1 of the Build your first dashboard. Create an analysis for the dataset. The following steps show you how to create visuals to show data from the current year,…

maybe the part “Filter the data” will help.
BR