comparing values in a portal

[brifra]

Is there any way to compare values through a portal?

I have a people database pulling each individuals donations through a portal and want to be able to evaluate whether their most recent donation went up or down from the previous donation.

Ideas?

[comment]

You need to do this in the Donations table. A relationship from Donations to anther TO of Donations, let's call it PreviousDonations, based on:

Donations::DonorID = PreviousDonations::DonorID

AND

Donations::Date > PreviousDonations::Date

will show all previous donations of the same donor. This relationship needs to be sorted by date, descending.

Now you can have a calculation field in Donations, for example:

Case (

not IsEmpty ( PrevDonations::DonationID ) ;

Choose ( 1 + Sign ( Sum - PrevDonations::Sum ) ; "LESS" ; "SAME" ; "MORE" )

)

This field would go into the portal. You could even calculate the change in %, etc.