CREATE TABLE certificate (eid NUMBER, aid NUMBER)
CREATE TABLE aircraft (aid NUMBER, name CLOB, distance NUMBER)
CREATE TABLE flight (flno NUMBER, origin CLOB, destination CLOB, distance NUMBER, departure_date TIME, arrival_date TIME, price NUMBER, aid NUMBER)
CREATE TABLE employee (eid NUMBER, name CLOB, salary NUMBER)

Show ids for all aircrafts with more than 1000 distance.
SELECT aid FROM aircraft WHERE distance > 1000
SELECT "aid" FROM "aircraft" WHERE "distance" > 1000