MCQOPTIONS
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MCQOPTIONS
| 1. |
SQL allows duplicate tuples in relations, and correspondingly defines the multiplicity of tuples in the result of joins. Which one of the following queries always gives the same answer as the nestedselect * from R where a in (select S.a from S) |
| A. | select R.* from R, S where R.a = S.a |
| B. | select distinct R.* from R, S where R.a = S.a |
| C. | select R.* from R,(select distinct a from S) as S1 where R.a = S1.a |
| D. | select R.* from R,S where R.a = S.a and is unique R |
| Answer» D. select R.* from R,S where R.a = S.a and is unique R | |