Fetch date of last donation

Fetch date of last donation

Hi all,

I've got a question that I've been trying to figure out for a while now without success. 

Here is the scenario.

I work for an organization that provides foster care to blind orphans. (queue violin music in the background). I've made a Zoho database to track sponsors and their donations. I can register new sponsors, link them to a child, and record their donation. When an existing sponsor makes a donation all I have to do is select his/her name from a drop down list and the form will auto-fill other fields like "amount pledged", "date of donation" and "sponsor child's name". All I have to do is check the donation made to the pledged amount, enter the donation amount and voila. 

Most of our sponsors donate monthly so I've set up a field that "should" auto-fill and display the "date of last" donation of the selected sponsor. 

I want to be able to select an existing sponsor and not only display the name of the child they are sponsoring monthly but also the date of their last donation. 

Problem is: I can't get the "date of last donation" field to auto-fill with the actual date of their last donation....instead it auto-fills the date of their first donation.

This is the script I'm using:

reca = Donations[Sponsor = input.Sponsor];
Dold=reca.Donation_date;

Can you help me fix the script so that it fetches the "date of last donation" instead of the first?

much appreciated.

Matt