CREATE TABLE reviewer (rid NUMBER, name CLOB)
CREATE TABLE movie (mid NUMBER, title CLOB, year NUMBER, director CLOB)
CREATE TABLE rating (rid NUMBER, mid NUMBER, stars NUMBER, ratingdate TIME)

What are the names of the directors who made exactly one movie?
SELECT director FROM movie GROUP BY director HAVING COUNT(*) = 1
SELECT "director" FROM "movie" GROUP BY "director" HAVING COUNT(*) = 1