Question

在MySQL的命令行中，我试图打印在单场比赛中进球超过3个的团队的名称，无论是主队，客队还是两者。 / strong>

我有两个关系：

Team +---------+-----------+------+----+ | name | shortName | abbr | id | +---------+-----------+------+----+ Game +---------+--------------+--------------+------------+------------+ | game_id | home_team_id | away_team_id | score_home | score_away | +---------+--------------+--------------+------------+------------+

（ home_team_id 和 away_team_id 都是 Team.id 的外键）

我首先尝试找到球队得分超过3个进球的game_id：

> SELECT game_id, score_home, score_away FROM Game WHERE score_home > 3 OR score_away > 3; +---------+------------+------------+ | game_id | score_home | score_away | +---------+------------+------------+ | 7 | 6 | 2 | | 35 | 3 | 4 | | 70 | 4 | 1 | | 71 | 2 | 5 | | 84 | 5 | 1 | | 88 | 6 | 2 | | 97 | 1 | 5 | | 103 | 6 | 1 | +---------+------------+------------+

所以我很确定最多只能有8支进球超过3个的球队。然后，我尝试了INNER JOINS，但是我不确定在两个不同的外键和条件下如何使用，但这是我的尝试：

> SELECT Team.name as Team_Name, Game.game_id, Game.score_home, Game.score_away -> FROM Team -> INNER JOIN Game ON Team.id=home_team_id OR Team.id=away_team_id -> WHERE score_home > 3 OR score_away > 3; +-------------------+---------+------------+------------+ | Team_Name | game_id | score_home | score_away | +-------------------+---------+------------+------------+ | Arsenal | 71 | 2 | 5 | | Everton | 7 | 6 | 2 | | Manchester City | 70 | 4 | 1 | | Manchester City | 84 | 5 | 1 | | Manchester City | 103 | 6 | 1 | | Norwich City | 88 | 6 | 2 | | Tottenham Hotspur | 70 | 4 | 1 | | Tottenham Hotspur | 97 | 1 | 5 | | Newcastle United | 88 | 6 | 2 | | Newcastle United | 103 | 6 | 1 | | West Ham United | 35 | 3 | 4 | | Leicester City | 71 | 2 | 5 | | Sunderland | 7 | 6 | 2 | | Bournemouth | 35 | 3 | 4 | | Bournemouth | 84 | 5 | 1 | | Bournemouth | 97 | 1 | 5 | +-------------------+---------+------------+------------+

当我只希望得分超过3分的球队时，这同时给了我主队和客队的名字。请帮忙。

Answer 1

使用UNION在子查询的一列中获取所有团队ID，然后将团队加入其中。

SELECT t.name
       FROM (SELECT g.home_team_id team_id
                    FROM game g
                    WHERE score_home > 3
             UNION
             SELECT g.away_team_id team_id
                    FROM game g
                    WHERE score_away > 3) x
            INNER JOIN team t
                       ON t.id = x.team_id;

Answer 2

一种方法使用相关子查询：

select t.name
from team t
where exists (select 1
              from game g
              where g.home_team_id = t.id and
                    g.score_home > 3
             ) and
      exists (select 1
              from game g
              where g.away_team_id = t.id and
                    g.score_away > 3
             ) ;

此查询可以利用game(home_team_id, score_home)和game(away_team_id, score_away)上的索引。

Answer 3

如果在一次比赛中均得分超过3个进球，则以下查询将在单独的行中返回主场和客场-

SELECT 
T.Name as [Team_Name],
A.Team_Type,
A.Game_id,
A.Score
FROM
(
    SELECT 'Home' AS [Team_Type],game_id AS Game_id,home_team_id as team_ID, score_home as Score WHERE score_home>3
    UNION ALL
    SELECT 'Away' AS [Team_Type], game_id AS Game_id,away_team_id as team_ID, score_away as Score WHERE score_away>3
)A
INNER JOIN Team T 
ON T.id = A.team_ID
ORDER BY A.Game_id

如何在条件中使用JOIN

3 个答案: