Question

我正在尝试从下表（示例）构建SQL查询：

Example of table with name "performances"

这是运动表演的表格。我想根据每个学科的表格和一个或多个类别的集合选择最佳表现。每位运动员的成绩应该只有一次，尽管他的最佳表现值是表现表的两倍或更多。

Here is expected result from table "performances"

实际上我有这个SQL查询，但是从子查询加入所有具有最佳值的行，最好是Athle_id：

＆＃13;

SELECT 

p.athlete_id, p.value 

FROM

(SELECT athlete_id, MAX(value) AS best FROM performances 

WHERE discipline_id = 32 AND category_id IN (1,3,5,7,9) 

GROUP BY athlete_id) f

INNER JOIN performances p 

ON p.athlete_id = f.athlete_id AND p.conversion = f.best

ORDER BY p.value DESC, p.created

＆＃13;

请问，我怎样才能为每位运动员加入一排，这位运动员创造了最早的属性？

Answer 1

要根据最大值athlete获取每discipline个value的单行，您可以执行自我左连接，处理平局情况或单athlete如果有多个行具有相同的最大值，则可以使用case语句选择具有最早日期的行

select a.*
from performances a
left join performances b
on a.discipline_id = b.discipline_id
and a.athlete_id = b.athlete_id
and case when a.value = b.value
    then a.created > b.created
    else a.value < b.value
    end 
where b.discipline_id is null

DEMO

此外，您可以在where子句中添加过滤器

and a.discipline_id = 32 
and a.category_id IN (1,3,5,7,9)

DEMO

Answer 2

您不必使用联接，可以使用window function：

执行此操作

SELECT 
  p.athlete_id, 
  p.value 
FROM 
  (
    SELECT 
      athlete_id, 
      value, 
      ROW_NUMBER() over (partition by athlete_id order by value desc, created) rowid 
    FROM 
      performances 
   WHERE 
      discipline_id = 32 AND 
      category_id IN (1,3,5,7,9) 
  ) p 
where 
  p.rowid = 1

Answer 3

非常感谢，伙计们。在你的答案后，我终于找到了解决方案。

＆＃13;

SELECT r.* FROM 

(SELECT p.athlete_id, p.conversion, MIN(p.created) AS created FROM

(SELECT athlete_id, MAX(conversion) AS best 
FROM performances 
WHERE discipline_id = 32 AND category_id IN (1,3,5,7,9) 
GROUP BY athlete_id) f

INNER JOIN performances p ON p.athlete_id = f.athlete_id AND p.conversion = f.best
GROUP BY p.athlete_id) w INNER JOIN performances r 

ON w.athlete_id = r.athlete_id AND w.conversion = r.conversion 
AND ((w.created = r.created) OR (w.created IS NULL AND r.created IS NULL))

ORDER BY r.conversion DESC, r.created

＆＃13;

MySQL为每个运动员，类别选择最佳（和最老）表现

3 个答案: