Hi @Angie_Belle - I’m guessing your roll-up field is an array function. If so, you should make it a string first in the FIND formula by concatenating it with an empty string to get it to work:
FIND("2", Activities & "")
Certain fields, including rollups, generate arrays, not strings. An array is a collection of separate items, and those items could be strings, dates, numbers, etc. However, the
FIND function only knows how to find things in a single string. When you ask it to find something in an array, it doesn’t know what to do. Concatenating an array with an empty string (the
Activities & "" portion of @JonathanBowen’s sample) forces Airtable to take all of the separate items in the array and mash them together into a single string, which
FIND can then process.
One of the aggregation functions available for use in rollup fields is the
MIN function, which isolates the lowest value. Enter the following into the aggregation function field when setting up the rollup: