SQL ORDER BY in IN subquery returns no results

Question

I am using SQL (H2 database engine ver 1.4.181) and am trying to sum the top 5 points that a student has. The RESULTS table includes the studentID, eventID and points. Each student can only be entered in an event once. The following subquery is what I am trying to use to do this for the student with and id of 5.

SELECT SUM(points) FROM RESULTS 
    WHERE eventID IN
        (SELECT TOP 5 eventID FROM RESULTS 
             WHERE studentID = 5 ORDER BY points DESC) 
        AND studentID = 5;

However, this query is returning null. I have found that, if the ORDER BY points DESC is removed, then the rest of the query works. Does anyone know how to incorporate the ORDER BY, or why it doesn't work?

Thanks

Answer 1

This looks like a bug in H2. You could use a join. Complete test case:

create table results(eventId int, points int, studentId int);
insert into results values(1, 10, 1), (2, 20, 1), (3, 5, 1);
insert into results values(1, 10, 2), (2, 20, 2), (3, 5, 2);
insert into results values(1, 10, 3), (2, 20, 3), (3, 5, 3);

SELECT SUM(r.points) FROM RESULTS r,
(SELECT eventID FROM RESULTS 
  WHERE studentID = 2 
  ORDER BY points DESC
  LIMIT 2 ) r2
WHERE r2.eventID = r.eventId
AND studentID = 2;

Answer 2

try using join, you can use sql like this belw

select sum(x.points) from 
(select points , event_id  from RESULTS) X 
(select eventID from 
(SELECT  eventID, row_number() over (partition by points ORDER BY points DESC ) tops FROM RESULTS )  X
where tops<6 ) Y 
where X.eventID=y.eventID 
and X.studentID = 5;

Answer 3

Turns out I didn't need an IN query at all. The following worked perfectly:

SELECT SUM(points) FROM 
    (SELECT TOP 5 points FROM RESULTS 
        WHERE studentID = 5
        ORDER BY points DESC);