I came across this question yesterday. I am looking for an explanation for just one point.
Which of the following statements are TRUE about an SQL query?
P : An SQL query can contain a HAVING clause even if it does not have a GROUP BY clause
Q : An SQL query can contain a HAVING clause only if it has a GROUP BY clause
R : All attributes used in the GROUP BY clause must appear in the SELECT clause
S : Not all attributes used in the GROUP BY clause need to appear in the SELECT clause
(A) P and R.
(B) P and S.
(C) Q and R.
(D) Q and S.
I selected A as an answer. But actually B is the correct answer.
I want to know that some websites mention R is correct, whereas others say S is correct. Which statement is correct between the last two?