Database-Management-System
October 4, 2023SQL
October 4, 2023Database-Management-System
| Question 49 |
Given relations r(w, x) and s(y, z), the result of
select distinct w, x
from r, s is guaranteed to be same as r, provided
| r has no duplicates and s is non-empty | |
| r and s have no duplicates | |
| s has no duplicates and r is non-empty | |
| r and s have the same number of tuples |
Question 49 Explanation:
r has no duplicate, if r can have duplicates it can be remove in the final state. s in non-empty if s is empty then r*s becomes empty.
Correct Answer: A
Question 49 Explanation:
r has no duplicate, if r can have duplicates it can be remove in the final state. s in non-empty if s is empty then r*s becomes empty.