CREATE TABLE race (race_id NUMBER, name CLOB, class CLOB, date CLOB, track_id CLOB)
CREATE TABLE track (track_id NUMBER, name CLOB, location CLOB, seating NUMBER, year_opened NUMBER)

Give the class of races that is most common.
SELECT class FROM race GROUP BY class ORDER BY COUNT(*) DESC LIMIT 1
SELECT "class" FROM "race" GROUP BY "class" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY