多表查询练习

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `course`
-- ----------------------------
DROP TABLE IF EXISTS `course`;
CREATE TABLE `course` (
  `cid` varchar(10) NOT NULL COMMENT '课程编号',
  `cname` varchar(10) NOT NULL COMMENT '课程名称',
  `tid` varchar(10) NOT NULL COMMENT '教师编号',
  PRIMARY KEY (`cid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of course
-- ----------------------------
INSERT INTO `course` VALUES ('01', '语文', '02');
INSERT INTO `course` VALUES ('02', '数学', '01');
INSERT INTO `course` VALUES ('03', '英语', '03');
INSERT INTO `course` VALUES ('04', '物理', '04');

-- ----------------------------
-- Table structure for `score`
-- ----------------------------
DROP TABLE IF EXISTS `score`;
CREATE TABLE `score` (
  `sid` varchar(10) NOT NULL COMMENT '学生编号',
  `cid` varchar(10) NOT NULL COMMENT '课程编号',
  `score` decimal(18,1) NOT NULL COMMENT '成绩'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of score
-- ----------------------------
INSERT INTO `score` VALUES ('01', '01', '80.0');
INSERT INTO `score` VALUES ('01', '02', '90.0');
INSERT INTO `score` VALUES ('01', '03', '99.0');
INSERT INTO `score` VALUES ('02', '01', '70.0');
INSERT INTO `score` VALUES ('02', '02', '60.0');
INSERT INTO `score` VALUES ('02', '03', '80.0');
INSERT INTO `score` VALUES ('03', '01', '80.0');
INSERT INTO `score` VALUES ('03', '02', '80.0');
INSERT INTO `score` VALUES ('03', '03', '80.0');
INSERT INTO `score` VALUES ('04', '01', '50.0');
INSERT INTO `score` VALUES ('04', '02', '30.0');
INSERT INTO `score` VALUES ('04', '03', '20.0');
INSERT INTO `score` VALUES ('05', '01', '76.0');
INSERT INTO `score` VALUES ('05', '02', '87.0');
INSERT INTO `score` VALUES ('06', '01', '31.0');
INSERT INTO `score` VALUES ('06', '03', '34.0');
INSERT INTO `score` VALUES ('07', '02', '89.0');
INSERT INTO `score` VALUES ('07', '03', '98.0');

-- ----------------------------
-- Table structure for `student`
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `sid` varchar(10) NOT NULL COMMENT '学生学号',
  `sname` varchar(10) NOT NULL COMMENT '学生姓名',
  `sage` datetime NOT NULL COMMENT '学生年龄',
  `ssex` varchar(10) NOT NULL COMMENT '学生性别',
  PRIMARY KEY (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('01', '赵雷', '1990-01-01 00:00:00', '男');
INSERT INTO `student` VALUES ('02', '钱电', '1990-12-21 00:00:00', '男');
INSERT INTO `student` VALUES ('03', '孙风', '1990-05-06 00:00:00', '男');
INSERT INTO `student` VALUES ('04', '李云', '1990-08-06 00:00:00', '男');
INSERT INTO `student` VALUES ('05', '周梅', '1991-12-01 00:00:00', '女');
INSERT INTO `student` VALUES ('06', '吴兰', '1992-03-01 00:00:00', '女');
INSERT INTO `student` VALUES ('07', '郑竹', '1989-07-01 00:00:00', '女');
INSERT INTO `student` VALUES ('08', '王菊', '1990-01-20 00:00:00', '女');

-- ----------------------------
-- Table structure for `teacher`
-- ----------------------------
DROP TABLE IF EXISTS `teacher`;
CREATE TABLE `teacher` (
  `tid` varchar(10) NOT NULL COMMENT '教师编号',
  `tname` varchar(10) DEFAULT NULL COMMENT '教师姓名',
  PRIMARY KEY (`tid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of teacher
-- ----------------------------
INSERT INTO `teacher` VALUES ('01', '张三');
INSERT INTO `teacher` VALUES ('02', '李四');
INSERT INTO `teacher` VALUES ('03', '王五');
INSERT INTO `teacher` VALUES ('04', '三八');

 https://www.cnblogs.com/DaTouDaddy/p/6743243.html