I'd love to be able to set a field value based on information from the connected record using some logical / sql type lookups. For instance, I have a customer object with connected invoices. I'd like to be able to have a field in the customer table for 'most recent invoice' and 'most recent invoice line item count', where these look at the actual connected records at run time to populate the correct values.
Right now, I can set these based via form rules at submission through the interface builder, but it's not elegant, and frequently doesn't hit every use case. For instance, when I create an invoice, I change the 'most recent invoice' field in the connected customer account to the date of the invoice, but if I go back later and delete that invoice, there is no easy way to set the 'most recent invoice' field to the invoice immediately prior.
*Of note*, when displaying the table of customer accounts, where I'm hoping to show these two fields, I can show fields from connected invoices, but because there the customer - invoice connection is a one-to-many, it will show all of the invoice dates, with an option to separate them by a comma or a newline. If I could use a filter at that point to only show the one most recent, etc, it would also solve the problem.