CREATE TABLE people (people_id DECIMAL, name TEXT, height DECIMAL, weight DECIMAL, date_of_birth TEXT)
CREATE TABLE entrepreneur (entrepreneur_id DECIMAL, people_id DECIMAL, company TEXT, money_requested DECIMAL, investor TEXT)

Return the investor who have invested in the greatest number of entrepreneurs.
SELECT investor FROM entrepreneur GROUP BY investor ORDER BY COUNT(*) DESC LIMIT 1
SELECT "investor" FROM "entrepreneur" GROUP BY "investor" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1