CREATE TABLE event (stadium_id VARCHAR2, id VARCHAR2)
CREATE TABLE record (event_id VARCHAR2)
CREATE TABLE stadium (name VARCHAR2, id VARCHAR2)

Find the names of stadiums that the most swimmers have been to.
SELECT t3.name FROM record AS t1 JOIN event AS t2 ON t1.event_id = t2.id JOIN stadium AS t3 ON t3.id = t2.stadium_id GROUP BY t2.stadium_id ORDER BY COUNT(*) DESC LIMIT 1
SELECT "t3"."name" FROM "record" "t1" JOIN "event" "t2" ON "t1"."event_id" = "t2"."id" JOIN "stadium" "t3" ON "t2"."stadium_id" = "t3"."id" GROUP BY "t2"."stadium_id" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY