How to get Total Value in the KPI when no field selected

[userpd_2021]

Hi below is the expression that I used to compare the data in the UI. But there no selection the KPI shows Zero value.But I want to display the over all total value if there's no selection

Sum({<Apple={"$(=GetFieldSelections(Apple))"},[=Upper(Mango)]={"$(=GetFieldSelections(Apple))"}>} Value)

Or Is there a way to do the same from the back end ? script editor side