Problem $2.(20$ pts$)$ Understanding of SQL $-$ I

Consider the following relational schema. An employee can work in more than one department;

the pct$\_$time field of the Works relation shows the percentage of time that a given employee

works in a given department.

Emp$($eid: integer, ename: string, age: integer, salary: real$)$

Works$($eid: integer, did: integer, pct time: integer$)$

Dept$($did: integer, dname: string, budget: real, managerid: integer$)$

Use this schema and the material on SQL discussed in this class indicate which SQL statement

corresponds to the query been asked:

a$)(5$ pts$)$ Print the names and ages of each employee who works in both the Hardware

department and the Software department.

I. SELECT E$.$ename, E$.$age

FROM Emp AS E$,$ Works AS W$1,$ Works AS W$2,$ Dept AS D$1,$ Dept AS D$2,$

WHERE E$.$eid $=$ W$1.$eid AND W$1.$did $=$ D$1.$did AND D$1.$dname $=$Hardware$$

AND

E$.$eid $=$ W$2.$eid AND W$2.$did $=$ D$2.$did AND D$2.$dname $=$Software$$

II$.$ SELECT E$.$Ename, E$.$age

FROM Emp AS E$,$ Works AS W$,$ Dept AS D$,$

WHERE E$.$eid $=$ W$.$eid AND W$.$did $=$ D$.$did AND D$.$dname $=$Hardware$$

AND D$.$dname $=$Software$$

III. SELECT E$.$Ename, E$.$age

FROM Emp AS E$,$ Works AS W$,$ Dept AS D$,$

WHERE E$.$eid $=$ W$.$eid AND W$.$did $=$ D$.$did AND D$.$dname $=$Hardware$$

INTERSECT

SELECT E$.$Ename, E$.$age

FROM Emp AS E$,$ Works AS W$,$ Dept AS D$,$

WHERE E$.$eid $=$ W$.$eid AND W$.$did $=$ D$.$did AND D$.$dname $=$Software$$

IV$.$ Both I and II

V$.$ Both I and III

VI$.$ Both II and III

VII. All of the above

VIII. None of the above

Answer: $\_\_\_\_$