mysql如何获取多个最大列值

Question

I am trying to query tables using join but I can't get success here my tables

Score
id    ,  user_id    ,     score  ,   week
1     ,   123       ,      2     ,    1
2     ,   432       ,      2     ,    1  
3     ,   432       ,      3     ,    1
4     ,   123       ,      2     ,    2

I want to query top twenty users records on the bases of sum of week 1 and week 2's max total

I want the result should be

id      , user_id     , week1score    , week2score
1       ,  123        ,  2            ,  2
2       ,  432        ,  3            ,  0

The formula is order by descending sum(max(week1)+max(week2))

Thanks Inam

Answer 1

something like this would do

SELECT t1.user_id, 
       SUM(week1score) AS week1score, 
       SUM(week2score) AS week2score 
FROM   (SELECT user_id 
        FROM   `table` 
        GROUP  BY user_id) AS t1 
       JOIN (SELECT user_id, 
                    Max(IF(`week` = 1, score, 0)) AS week1score, 
                    Max(IF(`week` = 2, score, 0)) AS week2score 
             FROM   `table` 
             GROUP  BY user_id, 
                       `week`) t2 
         ON t2.user_id = t1.user_id 
GROUP  BY user_id 
ORDER  BY ( SUM(week1score) + SUM(week2score) ) DESC 

You need a composit index on the following columns

• (user_id,week,score)