/* Query 3A (page 172, 235 of the text book) is NOT supported by MS-SQL
   since EXCEPT is not implemented on MS-SQL

   Retrieve the name of each employee who works on all projects
   controlled by department number 4.

   The result must be
	Alicia  Zelaya
	Ahmad   Jabbar
*/

select	e.fname, e.lname
from	employee e
where	not exists
	((select	pnumber
	  from		project
	  where		dum = 4)
	 except
	 (select	pno
	  from		works_on w
	  where		w.essn = e.ssn) );

