Can you list the swimmer names and their times?
select name, time from swimmer
Hmm, I also want to know their record times and the related events.
select t1.time, t2.event_id from swimmer as t1 join record as t2 on t1.id = t2.swimmer_id
Please tell me the name of the swimmer who has at least 2 records.
select t1.name from swimmer as t1 join record as t2 on t1.id = t2.swimmer_id group by t2.swimmer_id having count ( * ) > = 2