A word or phrase that can categorize students that are either currently attending or have had attended sometime in the past

We need to create a new category that represents that a person has actually attended the school, whether that is current or historical. I proposed 'Once Student', which seems tense neutral, but also a little confusing. For addtional context this will need to result in three categories:

• Student (Is Attending)
• Former Student (Has Attended)
• Once Student (Is Attending or Has Attended)

Can anyone give a better phrase for the third category?

Solution 1:

Difficult. But someone who attends (or who has attended, and maybe even will attend in the future) is an attendee. While an attendee might usually attend an event, there's no reason it would not fit your context — especially if all you need is a column title attendee to hold Boolean values.

Lexico uses the word for past, present and future attendances:

The attendees did not realize that they were serving as guinea pigs to identify the operational problems.

Many of those seminar attendees are taking an enormous gamble on apartment rents remaining high.

There will be a panel discussion, followed by refreshments for all attendees.