#newgradiance #dbms #sql #joins Q5

Question

Suppose relations R(A,B) and S(B,C,D) have the tuples shown below:

R =

A B 1 2 3 4 5 6

S =

B C D 2 4 6 4 6 8 4 7 9

Compute the result of the join query:

     SELECT A, R.B, C, D
     FROM R, S
     WHERE R.B = S.B

Then, identify which of the following tuples is in the result.

a) (1,4,7,9)

b) (5,6,4,6)

c) (3,4,7,9)

d) (3,4,2,6)

Answer 1

I think options are wrong, correct output will be: 

Comments

Yes. I guess. I was also confused so I left it during exercise. Thanks for the explanation.

For the next try, the options were correct.

Answer 2

The answer is c. (3,4,7,9).

The result of the query is

A	R.B	C	D
1	2	4	6
3	4	6	8
3	4	7	9