MadeEasy Test Series 2018: Databases - Relational Algebra

Question

Consider the following database table
Supplier (Sid, Sname, rating)
Parts (Pid, Pname, color)
Catalog (Sid Pid, cost)
Which of the following SQL query correct representation to retrieve Sid’s who supplied every red part.

Comments

i think both queries doesn't give required o/p

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@Shaik Masthan sir

for Q2 i am convinecd that it will not retrieve all sid's who supplied every red part

but am not getting whats wrong with Q1??

Q1 is correct acc to me.

pls see this database , wont it will give S1 for Q1???

                                           CATALOG

SID	PID
S1	P1
S1	P2
S1	P3
S1	P4
S2	P3

                                         

                                     PARTS

PID	COLOR
P1	RED
P2	RED
P3	RED
P4	RED
P5	WHITE

 

 

 

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if i return null in both inner query the what will be the result