Question

我正在尝试从数据库表（'结果'）获取结果列表，但是，每个成员可能已经提交了多个结果，我希望找回他们的最佳时间。

下面的查询有效（虽然我不确定它是否有效），除非同一竞争对手有多个结果且得分相同。（例如，竞争者＃2得分时间为32.15秒两次）。在这种情况下，我为这个竞争者获得两排，而不是我想要的那一排。

SELECT result_id FROM ( 
    SELECT member_id,MIN(time) AS mintime FROM result 
        JOIN member_result ON result.id = member_result.result_id 
        WHERE event_id = ? 
        GROUP BY member_id ORDER BY mintime ) AS x 
JOIN result ON result.time = x.mintime
JOIN member_result ON member_result.result_id = result.id
AND member_result.member_id = x.member_id

任何解决问题的建议都会受到重视。

编辑：请求的表格结构;

member_result (TABLE)
 id int unsigned (10)
 result_id int unsigned (10)
 member_id int unsigned (10)
 club_id int unsigned (10)

result (TABLE)
 id int unsigned (10)
 time decimal (6)
 is50mPool BIT ()
 date date ()
 verified BIT ()
 verified_date timestamp ()
 verified_comment varchar (255)
 hasEmailed BIT ()
 enabled BIT ()
 event_id int unsigned (10

样本问题：结果：事件＃2的id＃1，时间60 member_result：id＃1，result_id 1，member_id 3 结果：事件＃2的id＃2，时间60 member_result：id＃2，result_id 2，member_id 3

我只想返回一行，使用result_id - 当前两行都返回，因为最小时间相等。

Answer 1

编辑：

您可以尝试使用MIN或MAX，具体取决于哪个更有趣于ID，然后只有一行：

像：

SELECT result_id FROM ( 
    SELECT member_id, MIN(member_result.id) as member_resultID ,MIN(time) AS mintime FROM result 
        JOIN member_result ON result.id = member_result.result_id 
        WHERE event_id = 2 
        GROUP BY member_id ORDER BY mintime ) 
AS x 
JOIN result ON result.time = x.mintime
JOIN member_result ON member_result.result_id = result.id
AND member_result.id = x.member_resultID

这仅返回第一个用户的给定事件的MIN时间。（所以只有一行而不是两行）

此处为SqlFiddle。

Answer 2

SELECT Distinct result_id FROM ( 
SELECT member_id,MIN(time) AS mintime FROM result 
    JOIN member_result ON result.id = member_result.result_id 
    WHERE event_id = ? 
    GROUP BY member_id ) AS x 
JOIN result ON result.time = x.mintime
JOIN member_result ON member_result.result_id = result.id
AND member_result.member_id = x.member_id

你试过这个吗？

Answer 3

实际上，事实证明这就像在外部查询上再次分组一样简单 - 由于我在限制之前没有ORDER BY的LIMIT语句，因为GROUP的原因通过查询打破了。

SELECT result_id FROM ( 
SELECT member_id,MIN(time) AS mintime FROM result 
    JOIN member_result ON result.id = member_result.result_id 
    WHERE event_id = ? 
    GROUP BY member_id ORDER BY mintime ) AS x 
JOIN result ON result.time = x.mintime
JOIN member_result ON member_result.result_id = result.id
AND member_result.member_id = x.member_id
GROUP BY member_result.member_id

感谢所有贡献者！

当聚合函数相等时，MySQL Group返回多个结果

3 个答案: