Question

我有四张桌子：人，教练，球员，比赛。我需要编写一个SQL SELECT语句，它将返回：我的id，姓名，出生日期，加入日期，我注册的教练的姓名，以及游戏的日期，时间和持续时间。

人员表包括：人员ID，姓名，出生日期和其他一些不必要的值。 coach表包含：coach id和一些其他不必要的值。玩家表包括：玩家ID，加入日期，加入。游戏桌包括：教练ID，玩家ID，游戏日期，游戏时间，游戏持续时间。

人员表基本上存储了教练和球员的所有名字和主要细节。表格链接正确。

我尝试了各种各样的陈述，但我完全糊涂了自己。这个例子有些蹩脚，我还有别的东西，但不知道怎么回事。

e.g。

SELECT person_id, full_name, date_of_birth, join_date
FROM (person JOIN player ON player_id = person_id)
WHERE person_id='100' AND person_id, full_name
FROM (person JOIN coach ON coach_id = person_id);

这些是CREATE语句：

CREATE TABLE person (
        person_id          CHAR(10)    NOT NULL,
        full_name          VARCHAR(54)    NOT NULL,
        date_of_birth      DATE,
        sex                CHAR(1),
  PRIMARY KEY (person_id)
) engine innodb;
CREATE TABLE coach (
        coach_id          CHAR(10)    NOT NULL,
        phone_no           CHAR(10)    NOT NULL,
        hall_no            CHAR(4)    NOT NULL,
  PRIMARY KEY (coach_id),
  FOREIGN KEY (coach_id) REFERENCES person (person_id)
) engine innodb;
CREATE TABLE player (
        player_id        CHAR(10)    NOT NULL,
        join_date   DATE        NOT NULL,
        joined_with   CHAR(10),
  PRIMARY KEY (player_id),
  FOREIGN KEY (player_id) REFERENCES person (person_id),
  FOREIGN KEY (joined_with) REFERENCES coach (coach_id)
) engine innodb;
CREATE TABLE game (
        coach_id        CHAR(10)    NOT NULL,
        player_id       CHAR(10)    NOT NULL,
        game_date        DATE        NOT NULL,
        game_time        TIME        NOT NULL,
        game_duration    INTEGER    DEFAULT 10,
  PRIMARY KEY (coach_id, player_id, game_date, game_time),
  FOREIGN KEY (coach_id) REFERENCES coach (coach_id),
  FOREIGN KEY (player_id) REFERENCES player (player_id)
) engine innodb;

Answer 1

你的SQL是关闭的。看起来您只是使用多个INNER JOINs来尝试以下内容：

SELECT p.person_id, p.full_name, p.date_of_birth, pl.join_date, 
  c.coach_id, p2.full_name as coach_name, g.*
FROM person p
    JOIN player pl ON p.person_id = pl.player_id        
    JOIN game g ON p.person_id = g.player_id
    JOIN coach c ON c.coach_id = g.coach_id
    JOIN person p2 on c.coach_id= p2.person_id          
WHERE p.person_id='1' 
ORDER BY p.person_id, p.full_name

如果您不需要教练的名字，您将不需要再次与人重新加入 - 我只是假设这将是有用的信息。

SQL Fiddle Demo

Answer 2

我希望这会有所帮助。

SELECT person.person_id, person.full_name, person.date_of_birth, player.join_date 
 FROM person
INNER JOIN player
   ON player.player_id = person.person_id
WHERE person.person_id = '100'

如何编写从多个表返回值的SQL SELECT语句？

2 个答案: