GATE Papers >> CSE >> 2009 >> Question No 55

Question No. 55 CSE | GATE 2009

Consider the following relational schema:

Suppliers(sid:integer, sname:string, city:string, street:string)
Parts(pid:integer, pname:string, color:string)
Catalog(sid:integer, pid:integer, cost:real)

Consider the following relational query on the above database:

SELECT S.sname
FROM Suppliers S
WHERE S.sid NOT IN (SELECT C.sid
                                FROM Catalog C
                                WHERE C.pid NOT (SELECT P.pid
                                                            FROM Parts P
                                                            WHERE P.color<> 'blue'))

Assume that relations corresponding to the above schema are not empty. Which one of the following is the correct interpretation of the above query?


Answer : (A) Find the names of all suppliers who have supplied a non-blue part.


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