Exercise 12.3 For each of the following SQL queries, for each relation involved, list the...

Exercise 12.3 For each of the following SQL queries, for each relation involved, list the attributes that must be examined to compute the answer. All queries refer to the following relations:

Emp(eid: integer, did: integer, sal: integer, hobby: char(20))
Dept(did: integer, dname: char(20), floor: integer, budget: real)

1. SELECT * FROM Emp E
2. SELECT * FROM Emp E, Dept D
3. SELECT * FROM Emp E, Dept D WHERE E.did = D.did
4. SELECT E.eid, D.dname FROM Emp E, Dept D WHERE E.did = D.did