I’m not sure there will be a way to do this with a Rollup field, since there is no concept in the formula functions of an iterator to go through each item in the array of “values” and check how many times a particular “value” in the array occurs.
Can you explain what it is you are trying to accomplish more generally? Perhaps there is another way to achieve your ultimate goals here.
Sure! I am hoping to pull info from one table into another (by means of lookup or rollup or some other means), but I only want the unique values that appear more than twice.
Course Name | Center (or classroom) | Disciplines
Center | Courses (as linked from Courses Table) | Disciplines (should pull from the Courses Table - but only those unique values that appear more than twice)
Welcome to the Airtable community!
Do you want something like the last column in this screen capture?
This setup uses a junction table and a system of lookups, formulas, and conditional rollups.
I don’t have time to do a write-up now, but let me know if this is what you want, and I will see if I can find time to do a writeup. (Or if you want a personal walkthrough, you can book an an appointment with me from the link in my profile.)