Tell me the payment amount for the payment id 4.
select amount from payment where payment_id = 4
How about its date?
select payment_date from payment where payment_id = 4
Tell me all the payment dates for the payments with an amount larger than 10 and the payments handled by a staff person with the first name Elsa.
select payment_date from payment where amount > 10 union select t1.payment_date from payment as t1 join staff as t2 on t1.staff_id = t2.staff_id where t2.first_name = 'Elsa'