The following relations keep track of airline flight information:
Flights(flno: integer, from: string, to: string, distance:
integer, departs: time, arrives: time, price: real)
Aircraft(aid: integer, aflame: string, cruisingrange: integer)
Certifled( eid: integer, aid: integer)
Employees( eid: integer, ename: string, salary: integer)
Note that the Employees relation describes pilots and other kinds of employees as well; every pilot is certified for some aircraft, and only pilots are certified to fly. Write each of the following queries in SQL.