How many films are there in total?
select count ( distinct title ) from film
How many of those films do not have any market estimation?
select count ( title ) from film where film_id not in ( select film_id from film_market_estimation )
Yes, could you tell me those films' IDs?
select film_id from film where film_id not in ( select film_id from film_market_estimation )
What are the titles of the films with those IDs?
select title from film where film_id in ( select film_id from film where film_id not in ( select film_id from film_market_estimation ) )