Sum the values based on conditions

[kiru_18]

Hi,

I need to sum 2 values based on some condition. I have entrydate, invoicedate, entryquantity, invoicequantity fields.

Requirement: If entrydate is selected it should sum entryquantiy and result is sum of entryquantity, if invoicedate is selected then it should Sum the invoicequantity and result is sum of invoicequantity.

This expression i need to build in one column in pivot table. 

[Or]

Sum(If(GetSelectedCount(entrydate)>0,entryquantiy, if(GetSelectedCount(invoicedate)>0,invoicequantity)))