Explain this SQL query in plain English.

Question

Please explain, in plain English, what question this SQL query answers:

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

I'm assuming you're asking what does that query do in plain English:

How much would it cost to book all rooms at the "Paris Hilton" hotel that are vacant today?

Answer 2

question would be like,

find out list of room that are not booked so far till today in the hotel "Paris Hilton" and return the sum of that amount.

Answer 3

This query appears to return the sum of the prices of all the rooms in the Paris Hilton hotel which aren't booked for today.

Answer 4

This is probably supposed to represent the total price of rooms available as of today at the "Paris Hilton" hotel. Why they are filtering on both HotelNo and HotelName.

I guess the question would be:

What is the total value of rooms available as of today at the "Paris Hilton" hotel?