-- Example 0.1 (slide 13)
-- SQL queries against the Seats(seat,reserved) table

-- (1) How many seats are reserved already, how many are still free?
SELECT   reserved, COUNT(*)
FROM     Seats
GROUP BY reserved;


-- (2) List all groups of free seats of size 3.
SELECT   s1.seat, s2.seat, s3.seat
FROM     Seats s1, Seats s2, Seats s3
WHERE    s1.seat + 1 = s2.seat
AND      s2.seat + 1 = s3.seat
AND      s1.reserved = 'f'
AND      s2.reserved = 'f'
AND      s3.reserved = 'f';

-- (3) List all groups of free seats of size n (n >= 1).

-- Hint: Construct a SQL query that lists the first and last seat
-- of a group. Sample output (assume n = 5):
--
--   FIRST       LAST       
--   ----------- -----------
--          1           5
--          2           6
--          8           13