用简单的英语解释这个SQL查询

Question

请用简单的英语解释这个SQL查询回答的问题:

SELECT SUM(price) FROM Room r, Hotel h

WHERE r.hotelNo = h.hotelNo and hotelName = 'Paris Hilton' and
roomNo NOT IN

(SELECT roomNo FROM Booking b, Hotel h
WHERE (dateFrom <= CURRENT_DATE AND
dateTo >= CURRENT_DATE) AND
b.hotelNo = h.hotelNo AND hotelName = 'Paris Hilton');

Answer 1

我假设你问的是那个查询用简单的英语做了什么:

预订今天空置的"Paris Hilton"酒店的所有客房需要多少费用？