How to do a comparaison/search of a single field to a list (like "intersect")

Hello everyone!

I have to find a unique item in a list quite regularly, and I am often stuck.
Sometimes I manage to get around it but I waste a lot of time finding a solution. So I decided to ask here if there is no faster solution.

Let’s imagine that people (table people) are invited to an event A (table event) for which there are several menus (table menu)

There are 5 diets for in an option set ‘diet’.

Let’s imagine that Menu 1 is for the diets:
Organic
Vegan
Vegetarian

And menu 2:
Classic

A person can only have one type of diet assigned.

How do I find the number of guests at event A who will have menu 1? I have a single field ‘diet’ and I want it to match one of the diets in a multidropdown.

“Intersect” only works for list to list comparison but on the ‘person’ table side it is not a list, it is a single field (a guest cannot have multiple diet).

Thank you !!

person's diet: converted to list

Oh you are my savior! thank you so much!! :grinning: