AtençãoTabelas R e S referentes a um banco de dados relacional.Rab122345Scd324261Consid...

Atenção


Tabelas R e S referentes a um banco de dados relacional.


R

a

b

1

2

2

3

4

5


S

c

d

3

2

4

2

6

1


Considerando as tabelas R e S apresentadas anteriormente, o resultado


a

b

1

2

2

3


seria obtido pela execução do comando SQL:

A

select * from R

where not exists (select * FROM S where a=c)

B

select * from R

where not exists (select * FROM S where a=d)

C

select * from S

where not exists (select * FROM R where a=c)

D

select * from S

where not exists (select * FROM R where a=d)

E

select * from R

where exists (select * FROM S where b=d)