如何获得与列出的组成员完全相同的组？

Question

一支足球队有 1 名或多名球员。一名球员属于 1 个或多个足球队。我有一个球员名单：'Bob', 'James', 'Sam' 我想知道哪支球队有这些球员。所以结果将是Red Team，因为Red Team 是唯一一个拥有完全'Bob', 'James', 'Sam' 的团队。请保留我所有的连接。我知道从技术上讲，您可以在 members 表中完成所有操作，但为了简单起见，我只是这样构建它。

CREATE TABLE teams(
  name VARCHAR(25) PRIMARY KEY
);

CREATE TABLE players(
  name VARCHAR(25) PRIMARY KEY
);

CREATE TABLE members(
  team_name VARCHAR(25) NOT NULL,
  player_name VARCHAR(25) NOT NULL,
  CONSTRAINT FK_team_name FOREIGN KEY (team_name) REFERENCES teams(name),
  CONSTRAINT FK_player_name FOREIGN KEY (player_name) REFERENCES players(name)
);

INSERT INTO teams(name) VALUES ('Blue Team');
INSERT INTO teams(name) VALUES ('Red Team');
INSERT INTO teams(name) VALUES ('Green Team');
INSERT INTO teams(name) VALUES ('Purple Team');

INSERT INTO players(name) VALUES ('Bob');
INSERT INTO players(name) VALUES ('Sarah');
INSERT INTO players(name) VALUES ('James');
INSERT INTO players(name) VALUES ('Mike');
INSERT INTO players(name) VALUES ('Sam');

INSERT INTO members(team_name, player_name) VALUES ('Blue Team', 'Bob');
INSERT INTO members(team_name, player_name) VALUES ('Green Team', 'Bob');
INSERT INTO members(team_name, player_name) VALUES ('Green Team', 'Sam');
INSERT INTO members(team_name, player_name) VALUES ('Green Team', 'James');
INSERT INTO members(team_name, player_name) VALUES ('Green Team', 'Sarah');
INSERT INTO members(team_name, player_name) VALUES ('Red Team', 'Bob');
INSERT INTO members(team_name, player_name) VALUES ('Red Team', 'Sam');
INSERT INTO members(team_name, player_name) VALUES ('Red Team', 'James');
INSERT INTO members(team_name, player_name) VALUES ('Purple Team', 'Mike');
INSERT INTO members(team_name, player_name) VALUES ('Purple Team', 'Sam');

我的 SQL 语句：

SELECT DISTINCT
  t.name
FROM teams t
LEFT JOIN members m
  ON t.name = m.team_name
LEFT JOIN players p
  ON m.player_name = p.name
WHERE
  m.player_name in ('Bob', 'James', 'Sam')

Answer 1

您可以使用聚合和having 子句。如果您想要正是这些成员，那么您可以在having 子句中进行过滤。以下假设成员不能在团队中重复：

SELECT t.name
FROM teams t JOIN
     members m
     ON t.name = m.team_name JOIN
     players p
     ON m.player_name = p.name
GROUP BY t.name
HAVING SUM(CASE WHEN m.player_name IN ('Bob', 'James', 'Sam') THEN 1 ELSE 0 END) = 3 AND
       COUNT(*) = 3;

编辑：

另一种方法是使用LISTAGG()：

SELECT t.name
FROM teams t JOIN
     members m
     ON t.name = m.team_name JOIN
     players p
     ON m.player_name = p.name
GROUP BY t.name
HAVING LISTAGG(m.player_name, ',') WITHIN GROUP (ORDER BY m.player_name) = 'Bob,James,Sam';

Here 是一个 dbfiddle。

如果您只想传入一个参数，这会很方便。但是，名称必须按照正确的顺序进行比较。