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

Show the name of employees with three lowest salaries.
SELECT name FROM employee ORDER BY salary LIMIT 3
SELECT "name" FROM "employee" ORDER BY "salary" NULLS FIRST LIMIT 3