数据库--查询

多对多查询
表：

CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
CREATE TABLE `stud_course` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `stud_id` int(11) DEFAULT NULL,
  `cou_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
CREATE TABLE `course` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

查询：

SELECT
    s.*, c. NAME
FROM
    student AS s
INNER JOIN stud_course AS sc ON s.id = sc.stud_id
INNER JOIN course AS c ON sc.cou_id = c.id
WHERE
    c. NAME = '数学'