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我在这里呼吁 MySQL 勇士。我的问题是我需要在子查询的左外部联接中使用对外部查询表的引用。我知道这是不可能的，但我不知道如何用外部查询中的典型连接替换子查询过滤。

我将举一个典型的例子来说明我的问题。

这是奥运会，我有几支球队（比如乒乓球队），其中有 1 到 N 名球员。当所有球员都与对方球队的所有球员交手时，两支球队之间的比赛就结束了。简而言之，我有 3 张桌子：

Team (id, country); 
Player (id, team_id, name) 
Game (id, playerA_id, playerB_id).

我想搜索所有没有或不是每场比赛都与对方球队的所有球员（显然不在我的球队中）发生争议的球员。这是我的查询：

SELECT t.*, p.*
FROM player p
INNER JOIN team t ON t.id = p.team_id AND t.id != My_Team_ID
WHERE EXISTS (
    -- If an opposing team's player has played no game => game.id is NULL
    -- If he hasn't played against all of my teammates => there will be at least one row where game.id is NULL
    SELECT *
    FROM player
    INNER JOIN team ON team.id = player.team_id AND team.id = My_Team_ID
    LEFT OUTER JOIN game ON player.id IN (game.playerA_id, game.playerB_id) AND p.id IN (game.playerA_id, game.playerB_id)
    WHERE game.id IS NULL
)

我出于实际目的放置了一个转储：http: //pastebin.com/HW3L5ukz 我试图将 LEFT OUTER JOIN 的第二个条件放在子查询的 WHERE 中，但它没有返回正确的结果。

关于如何实现这一目标的任何想法？提前致谢

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1 回答 1

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SELECT p1.*, p2.*
FROM player p1
JOIN team t1
  ON t1.id = p1.team_id AND t1.id = My_Team_ID
LEFT JOIN player p2
  ON p2.id != p1.id
JOIN team t2
  ON t2.id = p2.team_id AND t2.id != My_Team_ID
LEFT JOIN game g1
  ON (g1.playerA_id = p1.id OR g1.playerB_id = p1.id)
  AND (g1.playerA_id = p2.id OR g1.playerB_id = p2.id)
WHERE g1.id IS NULL

如果我为 My_Team_ID 使用 1，我会得到以下结果，其中显示了剩余的匹配项：

id  team_id name            id  team_id     name
1   1       Laurent Dupuis  6   2           Alec Russell
2   1       Stéphane Leroy  6   2           Alec Russell
3   1       Julien le Guen  4   2           Mark Johnsson
3   1       Julien le Guen  6   2           Alec Russell
于 2012-08-02T14:35:46.797 回答