SQL: Return only first occurrence

Question

I seldomly use SQL and I cannot find anything similar in my archive so I\'m asking this simple query question: I need a query which one returns personID and onl

Answer 1

Add this to your SQL:

and where not exists
    (select 1 from personAttendances t2 
    where t.personID=t2.personID 
    and t2.seenID < t.seenID)