Hello!  Can you provide me with a list of the first names of all customers who rented films before '2005-08-23 02:06:01'?
select first_name from customer where customer_id in ( select customer_id from rental where rental_date < '2005-08-23 02:06:01' )
Thank you!  That's a lot of people! Can you filter the list to show me only the active customers?
select first_name from customer where customer_id in ( select customer_id from rental where rental_date < '2005-08-23 02:06:01' ) and active = 1