SELECT eid FROM Employee EXCEPT SELECT eid FROM Certificate
What are the ids of all employees that don't have certificates?
create table flight(
	flno number(4,0) primary key,
	origin varchar2(20),
	destination varchar2(20),
	distance number(6,0),
	departure_date date,
	arrival_date date,
	price number(7,2),
    aid number(9,0),
    foreign key("aid") references `aircraft`("aid"));
create table aircraft(
	aid number(9,0) primary key,
	name varchar2(30),
	distance number(6,0));
create table employee(
	eid number(9,0) primary key,
	name varchar2(30),
	salary number(10,2));
create table certificate(
	eid number(9,0),
	aid number(9,0),
	primary key(eid,aid),
	foreign key("eid") references `employee`("eid"),
	foreign key("aid") references `aircraft`("aid")); 
INSERT INTO flight (FLNO, origin, destination, distance, departure_date, arrival_date, price,aid) VALUES (99.0,'Los Angeles','Washington D.C.',2308.0,'04/12/2005 09:30','04/12/2005 09:40',235.98, 1);
INSERT into aircraft (AID,name,distance) values ('1','Boeing 747-400','8430');
INSERT into employee (EID,name,salary) values ('242518965','James Smith','120433');
INSERT into certificate (EID,AID) values ('11564812','2');