GATE CSE 1988 | Question: 12iv

Question

Select      SNAME
from        S
Where       SNOin
            (select     SNO
            from        SP
            where       PNOin
                        (select     PNO
                        from        P
                        Where       COLOUR='BLUE'))

What relations are being used in the above SQL query? Given at least two attributes of each of these relations.

Answer 1

There are $3$ relations here:

• S(SNAME, SNO)
• SP(SNO, PNO)
• P(PNO, COLOUR)

Answer 2

relation S(sname , sno) and relation P(pno,colour)

Answer 3

S(SNAME , SNO)
SP(SNO , PNO)
P(PNO, COLOR)

SP is relation between S and P where sno and pno together being an primary key