获取用户的前 5 条记录、平均记录和平均排名

Question

I have a table for user records that hold scores (and need to get only users that are members). I need to get the top 5 scores for each user during this year, average the scores and return the top 10 users.

NOTE: Also the user must have a minimum of 5 entries.

SCORE TABLE:

user_id | score | date_submitted
   1       99     2017-11-07 22:00:00
   2       55     2017-10-33 11:33:35
   1       12     2017-09-33 11:33:35

USER TABLE

 id | is_member
  1      1
  2      1
  3      0

Here is what I have so far:

SELECT s.user_id, 
(SELECT AVG(s.score) FROM score s2 WHERE s2.user_id = s.user_id ORDER BY score DESC LIMIT 5) gr 
FROM score s, users u 
WHERE u.id = s.user_id 
AND u.is_member = 1 
AND YEAR(s.date_submitted) = YEAR(CURDATE())
GROUP BY s.user_id 
HAVING COUNT(*) >= 5 
ORDER BY gr DESC LIMIT 10

This returns:

1242 - Subquery returns more than 1 row

I understand that its the limit in the subquery, I am trying to figure out how to get the top 5 records for that user.

Answer 1

You don't need the subquery. I would also suggest using the join syntax:

SELECT     s.user_id, AVG(s.score) gr 
FROM       score s
INNER JOIN users u 
        ON u.id = s.user_id 
       AND u.is_member = 1 
WHERE      YEAR(s.date_submitted) = YEAR(CURDATE())
GROUP BY   s.user_id 
HAVING     COUNT(*) >= 5 
ORDER BY   gr DESC 
LIMIT      10

Answer 2

Following query will calculate avg of current year's top(highest) 5 scores of each user who is member and display top 10 users:

SELECT     s.user_id, AVG(s.score) gr 
FROM       (select * from score s
            where YEAR(date_submitted) = YEAR(CURDATE())
            and
              (select count(*)
                     from score
                     where user_id = s.user_id
                     and   score>=s.score
              )<=5
           ) s                                     
INNER JOIN users u 
        ON u.id = s.user_id 
       AND u.is_member = 1 
GROUP BY   s.user_id 
HAVING     COUNT(*) >= 5 
ORDER BY   gr DESC 
LIMIT      10;

Hope it helps.