Consider two ways to compute the names of employees who earn more than $100,000 and whose age is equal to their manager's age. First, a nested query:

Second, a query that uses a view definition:
SELECT E1.ename
FROM Emp E1, MgrAge A
WHERE E1.dname = A.dname AND E1.sal > 100 AND E1.age = A.age
CREATE VIEW MgrAge (dname, age)
AS SELECT D.dname, E.age
FROM Emp E, Dept D
WHERE D.mgr = E.ename
1. Describe a situation in which the first query is likely to outperform the second query.
2. Describe a situation in which the second query is likely to outperform the first query.
3. Can you construct an equivalent query that is likely to beat both these queries when every employee who earns more than $100,000 is either 35 or 40 years old? Explain briefly.

Transcribed Image Text:

SELECT El.ename FROM Emp El WHERE EI.sal > 100 AND EI.age= ( SELECT E2.age FROM Emp E2, Dept D2 WHERE EI.dname=D2.dname AND D2.mgT E2.ename) PFI