構文(問合せ)例-- FROM節の表式として、副問合せを使う。
SELECT VirtualFlightTable.flight_ID
FROM
(SELECT flight_ID, orig_airport, dest_airport
FROM Flights
WHERE (orig_airport = 'SFO' OR dest_airport = 'SCL') )
AS VirtualFlightTable
-- FROM節の表式として、副問合せ(values式)を使う。
SELECT mycol1
FROM
(VALUES (1, 2), (3, 4))
AS mytable (mycol1, mycol2)
-- EXISTSにて副問合せを使う
SELECT *
FROM Flights
WHERE EXISTS
(SELECT * FROM Flights WHERE dest_airport = 'SFO'
AND orig_airport = 'GRU')
-- INにて副問合せを使う
SELECT flight_id, segment_number
FROM Flights
WHERE flight_id IN
(SELECT flight_ID
FROM Flights WHERE orig_airport = 'SFO'
OR dest_airport = 'SCL')
-- 定量比較にて副問合せを使う
SELECT NAME, COMM
FROM STAFF
WHERE COMM >
(SELECT AVG(BONUS + 800)
FROM EMPLOYEE
WHERE COMM < 5000)