SQl Query

Question

Consider the following ORACLE relations:
R(A,B,C)={〈1,2,3〉,〈1,2,0〉,〈1,3,1〉,〈6,2,3〉,〈1,4,2〉,〈3,1,4〉 }
S(B,C,D)={〈2,3,7〉,〈1,4,5〉,〈1,2,3〉,〈2,3,4〉,〈3,1,4〉 }
Consider the following two SQL queries
SQ1: SELECT R.B,AVG(S.B)
FROM R,S
WHERE S.A=S.C AND S.D<7
GROUP BY R.B;
SQ2: SELECT DISTINCT S.B,MIN(S.C)
FROM S GROUP BY S.B
HAVING COUNT (DISTINCT S.D)>1;
If M is the number of tuples returned by SQ1 and N is the number of tuples returned by SQ2 then M=______,N=______ .

Answer 1

SQ1: {Correction done in bold}

SELECT R.B,AVG(S.B)
FROM R,S
WHERE R.A=S.C AND S.D<7
GROUP BY R.B;

o/p :

R.B	AVG(S.B)
1	2
2	3
3	3
4	3

M=4

SQ2:

SELECT DISTINCT S.B,MIN(S.C)
FROM S GROUP BY S.B
HAVING COUNT (DISTINCT S.D)>1;

O/P:

S.B	MIN(S.C)
1	2
2	3

N=2

Comments

Can you please explain why the last tuple of S is not selected in second Query. ?