#DBMS #SQL

Question

For the relations:

A(pid, cid)

B(pid, pname, powner)

C(cid, cname, cdesciption)

How will the query be executed :

SELECT pname, cname FROM A, B, C
WHERE B.powner = $somevalue
AND EXISTS(SELECT * FROM A WHERE A.cid = C.cid AND A.pid = B.pid)

Comments

first take cartesian product of A, B, C...

for each row in the result... Calculate the sub query where A is different to CARTESIAN PRODUCT table A