SQL Query Equivalence: IN vs. JOIN with Duplicates | GATE CS 2014 Set 2 Question 31

Computer Sciences > GATE 2014 SET-2 > SQL

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 nested query shown below:
SELECT * FROM R WHERE a IN (SELECT S.a FROM S)

SELECT R.* FROM R, S WHERE R.a = S.a

SELECT DISTINCT R.* FROM R, S WHERE R.a = S.a

SELECT R.* FROM R, (SELECT DISTINCT a FROM S) AS S1 WHERE R.a = S1.a

SELECT R.* FROM R, S WHERE R.a = S.a AND a IS UNIQUE R

Correct : c

Similar Questions

Related Topics

Similar Questions

Related Topics

Question Options

Sign in to ExamPrev