Rewrites: Magic Sets
•Create View DepAvgSal AS
•   (Select  E.did, Avg(E.sal) as avgsal
•     From   Emp E
•     Group By E.did)
•
•Select E.eid, E.sal
•From Emp E, Dept D, DepAvgSal V
•Where E.did=D.did AND D.did=V.did
•   And  E.age < 30 and D.budget > 100k
•   And  E.sal > V.avgsal