Question

班上有一群学生，每个人都可以加入多个俱乐部，但不能加入。

我想查看一下人们没有加入棒球俱乐部？

CREATE DATABASE `group` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;
USE `group`;

CREATE TABLE IF NOT EXISTS `club` (
  `ClubID` int(5) NOT NULL AUTO_INCREMENT,
  `ClubName` varchar(20) NOT NULL,
  PRIMARY KEY (`ClubID`)
);

INSERT INTO `club` (`ClubID`, `ClubName`) VALUES
(1, 'Baseball'),    (2, 'Basketball'),    (3, 'Tennis'),    (4, 'Snooker'),    (5, 'Football'),    (6, 'Swim'),    (7, 'Badminton'),    (8, 'Dance');

CREATE TABLE IF NOT EXISTS `member` (
  `id` int(5) NOT NULL AUTO_INCREMENT,
  `ClubID` int(5) NOT NULL,
  `StudentID` int(5) NOT NULL,
  PRIMARY KEY (`id`)
);

INSERT INTO `member` (`id`, `ClubID`, `StudentID`) VALUES
(1, 1, 1),(2, 1, 5),(3, 1, 9),(4, 1, 18),(5, 2, 2),(6, 2, 4),(7, 2, 5),(8, 3, 3),(9, 3, 4),(10, 3, 6),(11, 3, 7),(12, 3, 8),(13, 3, 9),(14, 3, 10),(15, 3, 11),(16, 4, 11),(17, 4, 12),(18, 4, 13),(19, 4, 14),(20, 5, 2),(21, 5, 6),(22, 5, 8),(23, 5, 9),(24, 5, 10),(25, 5, 14),(26, 6, 1),(27, 6, 8),(28, 6, 14),(29, 7, 5),(30, 7, 6),(31, 7, 7),(32, 8, 11),(33, 8, 12);

CREATE TABLE IF NOT EXISTS `student` (
  `StudentID` int(5) NOT NULL AUTO_INCREMENT,
  `StudentName` varchar(20) NOT NULL,
  PRIMARY KEY (`StudentID`)
);

INSERT INTO `student` (`StudentID`, `StudentName`) VALUES
(1, 'Mary'),    (2, 'Paul'),    (3, 'Andy'),    (4, 'Tony'),    (5, 'Jack'),    (6, 'Sandy'),    (7, 'Nacy'),    (8, 'Cherry'),    (9, 'Cathy'),    (10, 'Jenny'),    (11, 'Kelly'),    (12, 'Ash'),    (13, 'Rose'),    (14, 'Bruce'),    (15, 'David'),    (16, 'Harry'),    (17, 'William'),    (18, 'Richard');

所有学生： https://drive.google.com/file/d/0B4PAmUA35G8FbFlxZGktamFsUkE/view

SELECT `Student`.StudentID, `Student`.StudentName, group_concat(distinct `Club`.`ClubName`) AS `ClubName`, group_concat(distinct `Club`.`ClubID`) AS ClubID FROM `Student` LEFT JOIN `Member` ON `Member`.`StudentID` = `Student`.`StudentID` LEFT JOIN `Club` ON `Member`.`ClubID` = `Club`.`ClubID` Group BY  `Student`.`StudentID`

棒球俱乐部的学生（ClubID = 1）：

SELECT `Student`.StudentID, `Student`.StudentName, group_concat(distinct `Club`.`ClubName`) AS `ClubName`, group_concat(distinct `Club`.`ClubID`) AS ClubID FROM `Student` LEFT JOIN `Member` ON `Member`.`StudentID` = `Student`.`StudentID` LEFT JOIN `Club` ON `Member`.`ClubID` = `Club`.`ClubID` WHERE `Club`.`ClubID`='1' Group BY  `Student`.`StudentID`

学生不在棒球俱乐部？ https://drive.google.com/file/d/0B4PAmUA35G8FRndRRmVWa3h4M1E/view?usp=sharing

谢谢。

Answer 1

编写类似查询的明确写入not exists（优于not in，如jarl评论）：

select  *
from    Students s
where   not exists
        (
        select  *
        from    Member m
        join    Club c
        on      c.ClubID = m.ClubID
        where   ClubName = 'Baseball'
                and s.StudentID = m.StudentID
        )

我想查看一下人们没有加入棒球俱乐部？

1 个答案: