Deduplicate Merge Fields and Update Only Merge Options

#1

I’m comparing event registration reports from the last four years (2016 through 2019).

Email address is my primary key and the field I’m merging and comparing duplicates on.

If I have a column for “Year Registered” and one contact registered with the same email address in 2016 and 2017, how do I show “Year Registered” as “2016,2017” instead of 2017 overwriting 2016? Currently, the deduplicate process has me choose 2016 or 2017 as a single value.

The intent of the base is working with registration data. However, I have some membership data fields I’d like to bring in if the registrant has become a member, and again, using the email address to match.

Not every registrant is a member. Not every member is a registrant. But the two audiences have some overlap. The registrant audience is around 2,000. The membership audience is around 20,000.

Let’s say all registrants DO match up with a member, and in that case, Airtable’s import merge is going to create 18,000 rows for people who’ve never registered. How do I ONLY import and merge if there’s an email match to that membership data?