Question

我希望对属于某个团队的球员的总和进行累加。我有一个球员桌和一个团队桌。目前，我没有任何问题，只是由于某种原因它不会汇总查询的最后一部分。这是我的代码示例：

Select SUM(points)
from (select points
from player
Join team on player.full_name=team.player1
Where team.team_id = 8
and week =9
UNION
Select points
FROM player 
JOIN team on player.full_name=team.player2 
Where team.team_id = 8
and week =9
UNION
Select points
FROM player 
JOIN team on player.full_name=team.player3
Where team.team_id = 8
and week =9
UNION
Select points
FROM player 
JOIN team on player.full_name=team.player4
Where team.team_id = 8
and week =9

任何关于为什么会发生这种情况或更好的潜在方式来完成此操作的想法，将不胜感激！

Answer 1

您的查询似乎不完整，您必须使用UNION ALL来获得总数（f 2或更多的玩家拥有相同的分数UNION DISTINCT将消除这些行）：

SELECT
    SUM( points )
FROM (
    SELECT
        points
    FROM player
    JOIN team ON player.full_name = team.player1
    WHERE team.team_id = 8
    AND week = 9
    UNION ALL
    SELECT
        points
    FROM player
    JOIN team ON player.full_name = team.player2
    WHERE team.team_id = 8
    AND week = 9
    UNION ALL
    SELECT
        points
    FROM player
    JOIN team ON player.full_name = team.player3
    WHERE team.team_id = 8
    AND week = 9
    UNION ALL
    SELECT
        points
    FROM player
    JOIN team ON player.full_name = team.player4
    WHERE team.team_id = 8
) d

但是我相信您的团队表需要进行更改以提高效率

请注意，如果省略，则假设使用UNION = UNION DISTINCT。

这可能更有效：

SELECT
    SUM( player.points )
FROM player
WHERE player.full_name IN (
    SELECT distinct
        case when cj.n = 1 then team.player1
             when cj.n = 2 then team.player2
             when cj.n = 3 then team.player3
             when cj.n = 4 then team.player4
        end
    FROM team
    cross join (
       select 1 as n union all
       select 2 as n union all
       select 3 as n union all
       select 4 as n
       ) cj
    WHERE team.team_id = 8
    )
AND player.week = 9    ;

多次合并和联接操作后汇总列

1 个答案: