What are all the directors?
select distinct director from movie
How many movies did each of them direct?
select count(*), director from movie group by director
Show me those who directed more than one movie.
select director from movie group by director having count(*) > 1
Give me the titles and produced years of all movies directed by them.
select t1.title, t1.year from movie as t1 join movie as t2 on t1.director = t2.director where t1.title != t2.title