How can I do a ROW_NUMBER(), OVER and PARTITION in Zoho Reports?

How can I do a ROW_NUMBER(), OVER and PARTITION in Zoho Reports?

'm trying to do the following, in Zoho .. but I can't figure out how to do ROW_COUNT(), OVER and PARTITION(..)..

User | Class | Age Foo | "A" | 10 Bah | "A" | 12 Fred | "B" | 11 Jane | "A" | 11

and I'm after the eldest child, in each class.

Results

Class "A": Bah (12 years old) Class "B": Fred (11 years old).

This can be done quite simply with a ROW_NUMBER, OVER PARTITION

Can this be done in ZOHO?