| id | username |
|----|----------|
|  1 |    user1 |
|  2 |    user2 |
|  3 |    user3 |

| id | badgename | points | courseid |
|----|-----------|--------|----------|
|  1 |   badge a |     15 |        1 |
|  2 |   badge b |     10 |        1 |
|  3 |   badge c |     20 |        1 |
|  4 |   badge d |     15 |        2 |
|  5 |   badge e |     10 |        2 |
|  6 |   badge f |     25 |        2 |

| userid | badgeid |
|--------|---------|
|      1 |       1 |
|      2 |       2 |
|      3 |       3 |
|      1 |       4 |
|      2 |       5 |
|      3 |       6 |
|      1 |       5 |
|      2 |       4 |
|      3 |       3 |

| courseid | coursename |
|----------|------------|
|        1 |   course 1 |
|        2 |   course 2 |

SELECT userid, SUM(b.points), courseid,
   (SELECT AVG(points) FROM Badges WHERE courseid = b.courseid) as courseAVG
FROM
  Badges b INNER JOIN BadgeAssignments ba ON b.id = ba.badgeid
  INNER JOIN Users u ON ba.userid = u.id
GROUP BY userid, b.courseid

| userid | SUM(b.points) | courseid | courseAVG |
|--------|---------------|----------|-----------|
|      1 |            15 |        1 |        15 |
|      1 |            25 |        2 |   16.6667 |
|      2 |            10 |        1 |        15 |
|      2 |            25 |        2 |   16.6667 |
|      3 |            40 |        1 |        15 |
|      3 |            25 |        2 |   16.6667 |