How to calculate the number of active assignments for a person

Summary:

Question from a beginner: How can I calculate the number of active assignments for a person to isolate profiles with potential duplicate assignments?

Content (required):

Hello, I'm trying to build an analysis listing all staff with more than one active assignment, but I'm struggling to find a solution.

Any suggestion would be welcome. Ideally, the layout would include the assignment names on separate lines.

For context, we have a lot of HR users who mistakenly use "Add Assignment" instead of "Change Assignment", thus creating duplicate assignments (which creates time-consuming tickets for our helpdesk). The goal is to identify these issues before they become too complex to promptly clean up.