Question

我在我的网站上进行竞赛。每场比赛都可以有多个参赛作品我想根据得分检索最好的3个条目或更多（在抽奖的情况下）。得分计算为所有选票得分的总和。

这是SQLFiddle：http://sqlfiddle.com/#!9/c2480

表格ENTRY如下：

id    contest_id
1     1          
2     1          
3     1          
4     1          
5     1          
6     1          
7     1          
8     1          
9     1

表ENTRY_VOTE如下：

id    entry_id    score
-- entry 1 has 20 votes (5+10+5)
1     1           5
2     1           10
3     1           5
-- entry 2 has 20 votes (10+10)
4     2           10
5     2           10
-- entry 3 has 25 votes (5+5+5+10)
6     3           5
7     3           5
8     3           5
9     3           10
-- entry 4 has 10 votes (10)
10    4           10
-- entry 5 has 25 votes (10+10+5)
11    5           10
12    5           10
13    5           5
-- entry 6 has 5 votes (5)
14    6           5
-- entry 7 has 50 votes (10+10+10+10+10)
15    7           10
16    7           10
17    7           10
18    7           10
19    7           10
-- entry 8 has 20 votes (10+10)
20    8           10
21    8           10
-- entry 9 has 5 votes (5)
22    9           5

结果应该是（带抽奖）：

id (entry_id) contest_id  score
7             1           50
3             1           25
5             1           25
1             1           20
2             1           20
8             1           20

我正在尝试以下查询：

select * from (
     select entry.*, sum(score) as final_score from entry join entry_vote on 
     entry.entry_id = entry_vote.entry_id group by entry_id
) as entries
where final_score in (
    select distinct(final_score) from (
        select entry_id, sum(score) as final_score from entry_vote group by entry_id
    ) as final_scores order by final_score desc limit 3;
)

第一个子查询返回所有entry_vote得分总和的条目第二个子查询返回前3个区分总和得分（50,25和20）此查询返回错误。有什么不对，怎么解决？

Answer 1

您可以通过以下代码

执行此操作

SELECT entry_id, SUM(score) AS score FROM entry_vote GROUP BY entry_id ORDER BY score DESC LIMIT 3;

Answer 2

以下是SQLFiddle链接：http://sqlfiddle.com/#!9/c2480/50/0

我设法通过使用连接而不是子查询来解决查询。我在问题上发布的查询收到错误，因为第二个子查询正在完成＆＃34;;＆＃34;：

select distinct(final_score) from (
    select entry_id, sum(score) as final_score from entry_vote group by entry_id
) as final_scores order by final_score desc limit 3;

解决这个问题，下一个错误将是子查询内的限制。 Mysql不支持它们。

最终查询是：

select * from (
    select entry.*, sum(score) as score from entry 
    join entry_vote on entry.entry_id = entry_vote.entry_id where entry.contest_id = <CONTEST_ID> group by entry_id
) as entry_with_score join (
    select distinct(score) as score from (
        select sum(score) as score from entry_vote 
        join entry on entry_vote.entry_id = entry.id 
        join contest on audition.contest_id = contest.id where contest.id = <CONTEST_ID> group by entry_id
    ) as score_by_entry order by score desc limit 3
) as top_score on entry_with_score.score = top_score.score;

Answer 3

 SELECT entry_id,total
   FROM 
      ( SELECT x.*
             , IF(@prev=total,@i,@i:=@i+1) i,@prev:=total prev 
          FROM 
             ( SELECT entry_id
                    , SUM(score) total
                 FROM entry_vote
                GROUP 
                   BY entry_id
             ) x
             , (SELECT @i:=0,@prev:=NULL)vars 
         ORDER 
            BY total DESC
      ) a
  WHERE i <=3;

比赛中获胜者的Mysql查询，包括在另一个表中绘制得分

3 个答案: