text: SELECT COUNT(DISTINCT r.customer_id) number
  FROM rental r, customer, film f, inventory i, film_category f_c
  WHERE f_c.category_id = 1 
  AND r.customer_id NOT IN (
  SELECT r.customer_id 
  FROM rental r, customer, film f, inventory i, film_category f_c
  WHERE f_c.category_id = 11 AND f_c.film_id = f.film_id 
  AND customer.active = 1 AND f.film_id = i.film_id AND i.inventory_id = r.inventory_id AND r.customer_id = customer.customer_id)
  AND f_c.film_id = f.film_id
  AND customer.active = 1 AND f.film_id = i.film_id AND i.inventory_id = r.inventory_id AND r.customer_id = customer.customer_id;
  
  