Select the names of all students who have registered in at least one class offered by each department that offers a course.
SELECT SName, SNo FROM student s WHERE NOT EXISTS (SELECT * FROM department d WHERE d.Dept IN (SELECT Dept FROM course) AND NOT EXISTS (SELECT * FROM course c, registration r, class cl WHERE c.Dept=d.Dept AND c.CNo=r.CNo AND s.SNo=r.SNo AND r.CNo=cl.CNo AND r.Sec=cl.Sec)));
With the contents of the tables as in “Example: EXISTS with Correlated Subqueries”, the following rows are returned:
SName SNo ----- --- Helen Chu 1