relational algebra

Question

Comments

option D won't be equal to other three options.it will result every possible tuple of R. while all three option will result only those tuples for which R.B and S.B matches

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You are right.

But I am confused with option B.

 

As option B on join returns relation with attributes (A,B,B) not ( A,B) unlike option A and C  as it is inner join.

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Naa , it's natural join brother , R(AB)natural join S(B) would result same as option A and C.