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In SQL the statement select * from R, S is equivalent to

  • A.Select * from R natural join S.
  • B.Select * from R cross join S.
  • C.Select * from R union join S.
  • D.Select * from R inner join S.

Answer: B

Correct answer: Select * from R cross join S.

Listing two tables in the FROM clause with a comma and no join condition produces every combination of their rows - the Cartesian product, which is what CROSS JOIN means. A natural join would match on the common columns, which is a different result.

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