Question

I have a database with three tables in my database namely catering, room, room_booking and I am currently access room and room_booking in the following way – if two conditions are met:

SELECT name,capacity,licensed,$price FROM room
WHERE capacity BETWEEN '$minCapacity' AND '$maxCapacity' 
AND room_id NOT IN 
(SELECT room_id
FROM room_booking
WHERE date_booked = '$date')

The table catering has three columns room_id,grade,cost.

I need to select all the fields on table with a matching grade as so:

SELECT * FROM catering where grade=$grade;

How do I add this condition to my main SQL query with the other two conditions intact so that there three conditions in total working together?

Answer 1

Add a JOIN against catering. Substitute the correct column name for room.room_id if that isn’t correct (such as if it is supposed to be room.id).

SELECT name,capacity,licensed,$price
FROM 
 room
 JOIN catering ON room.room_id = catering.room_id
WHERE capacity BETWEEN '$minCapacity' AND '$maxCapacity' 
  AND room.room_id NOT IN 
   (SELECT room_id
    FROM room_booking
    WHERE date_booked = '$date'
   )
   AND catering.grade = '$grade'

Not sure why you have used $price in the select list. Perhaps that was a typo, or you were substituting a PHP variable?