Sum of all donations

Hi there. I am a newbie to Airtable but loving it so far. However, I am unfamiliar with using formulas in Airtable. I am testing it out for use as a fundraising database / CRM.

I would like to have a column (field) in the Donations table which sums up all donations to-date for the current year by Donor. I have a Donor table with unique Donor ID identifier which is linked into the Donations table.

So, for example, John Doe donated $100 in January 2020, and then he donated $50 in February.

I want a Total Donations To-Date 2020 field, which in January would automatically populate with $100 and in February after entering the new donation would update to $150.

How can I do that?

TIA for all responses.

Formula fields probably aren’t great for this. An alternative to the solution below might be a rollup field - which could be used in a Donor table if Donation records are linked to Donors, but I generally avoid rollup fields.

Grouped Summary Bar Solution

The donations table would ideally have a view like this:

  1. all the donation amounts in one field/column (which isn’t the primary field)
  2. filtered by the date range you want (in other words, only the records you want to sum are present)
  3. the donation amounts field should have a sum function in the summary bar
  4. grouped by donor id

Here’s what the summaries and grouping look like together: