Write a query that:

Computes the average length of all films that each actor appears in$.$

Rounds average length to the nearest minute and renames the result column "average".

Displays last name, first name, and average, in that order, for each actor.

Sorts the result in descending order by average, then ascending order by last name.

The query should exclude films with no actors and actors that do not appear in films.

Hint: Use the ROUND$()$ and AVG$()$ functions.