What are the id and the amount of refund of the booking that incurred the most times of payments?
create table payments (booking_id varchar, PRIMARY KEY (booking_id)); create table bookings (booking_id varchar, amount_of_refund varchar, PRIMARY KEY (booking_id))
select t1.booking_id, t1.amount_of_refund from bookings as t1 join payments as t2 on t1.booking_id = t2.booking_id group by t1.booking_id order by count(*) desc limit 1