Question

The below SQL query sums up each penalty mark per question in a session:

SELECT s.SessionId,q.QuestionId,SUM(pm.PenaltyMarks)
    FROM Session s
    INNER JOIN Question q ON s.SessionId = q.SessionId
    INNER JOIN Penalty_Marks pm ON q.QuestionId = pm.QuestionId
    WHERE (s.SessionId = 30)
    GROUP BY s.SessionId,q.QuestionId

Below is what the output displays:

SessionId  QuestionId  Sum(pm.PenaltyMarks)
30         77          4
30         38          3
30         39          4

But what I want to happen is now sum up all of the penalty marks within the Session. So in the above example it will add up the penalty marks together for session 30 to output the total penalty marks as 11. But my question is how can this be achieved?

So below is what it should look like:

SessionId  TotalPenaltyMarks
30         11

Answer 1

remove q.QuestionId

SELECT  s.SessionId, 
        SUM(pm.PenaltyMarks) TotalPenaltyMarks
FROM    Session s
        INNER JOIN Question q ON s.SessionId = q.SessionId
        INNER JOIN Penalty_Marks pm ON q.QuestionId = pm.QuestionId
WHERE   s.SessionId = 30
GROUP   BY s.SessionId

The GROUP BY clause is already optional since you are already filtering for a specific SessionId.