What percentage of films with a length of less than 100 belong to the Drama category?
Drama' is a name of a category; calculation = DIVIDE(SUM(length < 100 AND name = 'Drama'), COUNT(film_id)) * 100
SELECT CAST(SUM(IIF(T2.length < 100 AND T3.name = 'Drama', 1, 0)) AS REAL) * 100 / COUNT(T1.film_id) FROM film_category AS T1 INNER JOIN film AS T2 ON T1.film_id = T2.film_id INNER JOIN category AS T3 ON T1.category_id = T3.category_id