MySQL练习题

创建表和插入数据

 

DROP TABLE IF EXISTS `class`;
CREATE TABLE `class` (
  `cid` int(11) NOT NULL AUTO_INCREMENT,
  `caption` varchar(32) NOT NULL,
  PRIMARY KEY (`cid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of class
-- ----------------------------
INSERT INTO `class` VALUES ('1', '三年二班');
INSERT INTO `class` VALUES ('2', '三年三班');
INSERT INTO `class` VALUES ('3', '一年二班');
INSERT INTO `class` VALUES ('4', '二年九班');

-- ----------------------------
-- Table structure for course
-- ----------------------------
DROP TABLE IF EXISTS `course`;
CREATE TABLE `course` (
  `cid` int(11) NOT NULL AUTO_INCREMENT,
  `cname` varchar(32) NOT NULL,
  `teacher_id` int(11) NOT NULL,
  PRIMARY KEY (`cid`),
  KEY `fk_course_teacher` (`teacher_id`),
  CONSTRAINT `fk_course_teacher` FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`tid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of course
-- ----------------------------
INSERT INTO `course` VALUES ('1', '生物', '1');
INSERT INTO `course` VALUES ('2', '物理', '2');
INSERT INTO `course` VALUES ('3', '体育', '3');
INSERT INTO `course` VALUES ('4', '美术', '2');

-- ----------------------------
-- Table structure for score
-- ----------------------------
DROP TABLE IF EXISTS `score`;
CREATE TABLE `score` (
  `sid` int(11) NOT NULL AUTO_INCREMENT,
  `student_id` int(11) NOT NULL,
  `course_id` int(11) NOT NULL,
  `num` int(11) NOT NULL,
  PRIMARY KEY (`sid`),
  KEY `fk_score_student` (`student_id`),
  KEY `fk_score_course` (`course_id`),
  CONSTRAINT `fk_score_course` FOREIGN KEY (`course_id`) REFERENCES `course` (`cid`),
  CONSTRAINT `fk_score_student` FOREIGN KEY (`student_id`) REFERENCES `student` (`sid`)
) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of score
-- ----------------------------
INSERT INTO `score` VALUES ('1', '1', '1', '10');
INSERT INTO `score` VALUES ('2', '1', '2', '9');
INSERT INTO `score` VALUES ('5', '1', '4', '66');
INSERT INTO `score` VALUES ('6', '2', '1', '8');
INSERT INTO `score` VALUES ('8', '2', '3', '68');
INSERT INTO `score` VALUES ('9', '2', '4', '99');
INSERT INTO `score` VALUES ('10', '3', '1', '77');
INSERT INTO `score` VALUES ('11', '3', '2', '66');
INSERT INTO `score` VALUES ('12', '3', '3', '87');
INSERT INTO `score` VALUES ('13', '3', '4', '99');
INSERT INTO `score` VALUES ('14', '4', '1', '79');
INSERT INTO `score` VALUES ('15', '4', '2', '11');
INSERT INTO `score` VALUES ('16', '4', '3', '67');
INSERT INTO `score` VALUES ('17', '4', '4', '100');
INSERT INTO `score` VALUES ('18', '5', '1', '79');
INSERT INTO `score` VALUES ('19', '5', '2', '11');
INSERT INTO `score` VALUES ('20', '5', '3', '67');
INSERT INTO `score` VALUES ('21', '5', '4', '100');
INSERT INTO `score` VALUES ('22', '6', '1', '9');
INSERT INTO `score` VALUES ('23', '6', '2', '100');
INSERT INTO `score` VALUES ('24', '6', '3', '67');
INSERT INTO `score` VALUES ('25', '6', '4', '100');
INSERT INTO `score` VALUES ('26', '7', '1', '9');
INSERT INTO `score` VALUES ('27', '7', '2', '100');
INSERT INTO `score` VALUES ('28', '7', '3', '67');
INSERT INTO `score` VALUES ('29', '7', '4', '88');
INSERT INTO `score` VALUES ('30', '8', '1', '9');
INSERT INTO `score` VALUES ('31', '8', '2', '100');
INSERT INTO `score` VALUES ('32', '8', '3', '67');
INSERT INTO `score` VALUES ('33', '8', '4', '88');
INSERT INTO `score` VALUES ('34', '9', '1', '91');
INSERT INTO `score` VALUES ('35', '9', '2', '88');
INSERT INTO `score` VALUES ('36', '9', '3', '67');
INSERT INTO `score` VALUES ('37', '9', '4', '22');
INSERT INTO `score` VALUES ('38', '10', '1', '90');
INSERT INTO `score` VALUES ('39', '10', '2', '77');
INSERT INTO `score` VALUES ('40', '10', '3', '43');
INSERT INTO `score` VALUES ('41', '10', '4', '87');
INSERT INTO `score` VALUES ('42', '11', '1', '90');
INSERT INTO `score` VALUES ('43', '11', '2', '77');
INSERT INTO `score` VALUES ('44', '11', '3', '43');
INSERT INTO `score` VALUES ('45', '11', '4', '87');
INSERT INTO `score` VALUES ('46', '12', '1', '90');
INSERT INTO `score` VALUES ('47', '12', '2', '77');
INSERT INTO `score` VALUES ('48', '12', '3', '43');
INSERT INTO `score` VALUES ('49', '12', '4', '87');
INSERT INTO `score` VALUES ('52', '13', '3', '87');

-- ----------------------------
-- Table structure for student
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `sid` int(11) NOT NULL AUTO_INCREMENT,
  `gender` char(1) NOT NULL,
  `class_id` int(11) NOT NULL,
  `sname` varchar(32) NOT NULL,
  PRIMARY KEY (`sid`),
  KEY `fk_class` (`class_id`),
  CONSTRAINT `fk_class` FOREIGN KEY (`class_id`) REFERENCES `class` (`cid`)
) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES ('1', '男', '1', '理解');
INSERT INTO `student` VALUES ('2', '女', '1', '钢蛋');
INSERT INTO `student` VALUES ('3', '男', '1', '张三');
INSERT INTO `student` VALUES ('4', '男', '1', '张一');
INSERT INTO `student` VALUES ('5', '女', '1', '张二');
INSERT INTO `student` VALUES ('6', '男', '1', '张四');
INSERT INTO `student` VALUES ('7', '女', '2', '铁锤');
INSERT INTO `student` VALUES ('8', '男', '2', '李三');
INSERT INTO `student` VALUES ('9', '男', '2', '李一');
INSERT INTO `student` VALUES ('10', '女', '2', '李二');
INSERT INTO `student` VALUES ('11', '男', '2', '李四');
INSERT INTO `student` VALUES ('12', '女', '3', '如花');
INSERT INTO `student` VALUES ('13', '男', '3', '刘三');
INSERT INTO `student` VALUES ('14', '男', '3', '刘一');
INSERT INTO `student` VALUES ('15', '女', '3', '刘二');
INSERT INTO `student` VALUES ('16', '男', '3', '刘四');

-- ----------------------------
-- Table structure for teacher
-- ----------------------------
DROP TABLE IF EXISTS `teacher`;
CREATE TABLE `teacher` (
  `tid` int(11) NOT NULL AUTO_INCREMENT,
  `tname` varchar(32) NOT NULL,
  PRIMARY KEY (`tid`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of teacher
-- ----------------------------
INSERT INTO `teacher` VALUES ('1', '张磊老师');
INSERT INTO `teacher` VALUES ('2', '李平老师');
INSERT INTO `teacher` VALUES ('3', '刘海燕老师');
INSERT INTO `teacher` VALUES ('4', '朱云海老师');
INSERT INTO `teacher` VALUES ('5', '李杰老师');
SET FOREIGN_KEY_CHECKS=1;

1、查询所有的课程的名称以及对应的任课老师姓名
    SELECT cname 课程,tname 老师 from teacher,course WHERE teacher.tid=course.teacher_id;
+--------+-----------------+
| 课程   | 老师            |
+--------+-----------------+
| 生物   | 张磊老师        |
| 物理   | 李平老师        |
| 体育   | 刘海燕老师      |
| 美术   | 李平老师        |
+--------+-----------------+

2、查询学生表中男女生各有多少人
   SELECT gender 性别 ,COUNT(gender) 人数 from student GROUP BY gender;
+--------+--------+
| 性别   | 人数   |
+--------+--------+
| 女     |      6 |
| 男     |     10 |
+--------+--------+
   
3、查询物理成绩等于100的学生的姓名
    SELECT student.sname ,course.cname,score.num FROM score,student,course 
        WHERE num=100 and course_id=2  AND score.student_id=student.sid AND course.cid=score.course_id;
+--------+--------+-----+
| sname  | cname  | num |
+--------+--------+-----+
| 张四   | 物理   | 100 |
| 铁锤   | 物理   | 100 |
| 李三   | 物理   | 100 |
+--------+--------+-----+
        
4、查询平均成绩大于八十分的同学的姓名和平均成绩
   SELECT AVG(num),student.sname FROM score,student 
        WHERE score.student_id=student.sid GROUP BY student_id HAVING AVG(num) > 80;
+----------+--------+
| AVG(num) | sname  |
+----------+--------+
|  82.2500 | 张三   |
|  87.0000 | 刘三   |
+----------+--------+

5、查询所有学生的学号，姓名，选课数，总成绩
   SELECT student.sid 学号,COUNT(*) 课程数,student.sname 姓名,SUM(score.num) 总成绩 FROM score,student 
             WHERE student.sid=score.student_id GROUP BY student_id ORDER BY 学号;
+--------+-----------+--------+-----------+
| 学号   | 课程数    | 姓名   | 总成绩    |
+--------+-----------+--------+-----------+
|      1 |         3 | 理解   |        85 |
|      2 |         3 | 钢蛋   |       175 |
|      3 |         4 | 张三   |       329 |
|      4 |         4 | 张一   |       257 |
|      5 |         4 | 张二   |       257 |
|      6 |         4 | 张四   |       276 |
|      7 |         4 | 铁锤   |       264 |
|      8 |         4 | 李三   |       264 |
|      9 |         4 | 李一   |       268 |
|     10 |         4 | 李二   |       297 |
|     11 |         4 | 李四   |       297 |
|     12 |         4 | 如花   |       297 |
|     13 |         1 | 刘三   |        87 |
+--------+-----------+--------+-----------+

6、查询姓李老师的个数
   SELECT count(*) FROM teacher WHERE tname LIKE '李%';
+----------+
| count(*) |
+----------+
|        2 |
+----------+

7、查询没有报李平老师课的学生姓名
   SELECT sid 学号,sname 姓名 from student WHERE sid NOT IN
        (SELECT student_id FROM score  RIGHT  JOIN 
            (SELECT cid FROM course LEFT JOIN teacher ON teacher.tid=course.teacher_id WHERE tname LIKE "李平%") AS A
                ON score.course_id=A.cid GROUP BY student_id);
+--------+--------+
| 学号   | 姓名   |
+--------+--------+
|     13 | 刘三   |
|     14 | 刘一   |
|     15 | 刘二   |
|     16 | 刘四   |
+--------+--------+
 
8、 查询物理课程比生物课程高的学生的学号
    SELECT * from (SELECT student_id ,cname,num  FROM score LEFT JOIN course ON score.course_id=course.cid WHERE cname="物理") AS A 
        INNER JOIN  (SELECT student_id,cname,num  FROM score LEFT JOIN course ON score.course_id=course.cid WHERE cname="生物")AS B 
            ON A.student_id=B.student_id WHERE A.num > B.num;
+------------+--------+-----+------------+--------+-----+
| student_id | cname  | num | student_id | cname  | num |
+------------+--------+-----+------------+--------+-----+
|          6 | 物理   | 100 |          6 | 生物   |   9 |
|          7 | 物理   | 100 |          7 | 生物   |   9 |
|          8 | 物理   | 100 |          8 | 生物   |   9 |
+------------+--------+-----+------------+--------+-----+
 
9、 查询没有同时选修物理课程和体育课程的学生姓名
    SELECT sid 学号,sname 学员 FROM student WHERE sid not in (SELECT student_id FROM score
        LEFT JOIN course on course.cid=score.course_id 
            WHERE cname="物理" OR cname="体育" GROUP BY student_id HAVING count(cname) >1);
+--------+--------+
| 学号   | 学员   |
+--------+--------+
|      1 | 理解   |
|      2 | 钢蛋   |
|     13 | 刘三   |
|     14 | 刘一   |
|     15 | 刘二   |
|     16 | 刘四   |
+--------+--------+

10、查询挂科超过两门(包括两门)的学生姓名和班级
    SELECT sname,caption FROM (SELECT student_id,class_id,sname FROM score LEFT JOIN student ON student.sid=score.student_id  
        WHERE num < 60 GROUP BY score.student_id HAVING COUNT(*) > 1) AS A LEFT JOIN class ON class.cid=A.class_id;
+--------+--------------+
| sname  | caption      |
+--------+--------------+
| 理解   | 三年二班     |
+--------+--------------+

11、查询选修了所有课程的学生姓名
    SELECT student_id 学号,sname 姓名 FROM (SELECT * FROM score GROUP BY student_id HAVING COUNT(*) >= (SELECT COUNT(cname) FROM course )) AS A LEFT JOIN student
        ON A.student_id=student.sid;
+--------+--------+
| 学号   | 姓名   |
+--------+--------+
|      3 | 张三   |
|      4 | 张一   |
|      5 | 张二   |
|      6 | 张四   |
|      7 | 铁锤   |
|      8 | 李三   |
|      9 | 李一   |
|     10 | 李二   |
|     11 | 李四   |
|     12 | 如花   |
+--------+--------+

12、查询李平老师教的课程的所有成绩记录
    SELECT tname 老师, cname 课程,num 分数 FROM (SELECT cid,tname,cname FROM teacher LEFT JOIN course ON teacher.tid=course.teacher_id WHERE tname LIKE "李平%") AS A
        LEFT  JOIN score ON score.course_id=A.cid;
+--------------+--------+--------+
| 老师         | 课程   | 分数   |
+--------------+--------+--------+
| 李平老师     | 物理   |      9 |
| 李平老师     | 物理   |     66 |
| 李平老师     | 物理   |     11 |
| 李平老师     | 物理   |     11 |
| 李平老师     | 物理   |    100 |
| 李平老师     | 物理   |    100 |
| 李平老师     | 物理   |    100 |
| 李平老师     | 物理   |     88 |
| 李平老师     | 物理   |     77 |
| 李平老师     | 物理   |     77 |
| 李平老师     | 物理   |     77 |
| 李平老师     | 美术   |     66 |
| 李平老师     | 美术   |     99 |
| 李平老师     | 美术   |     99 |
| 李平老师     | 美术   |    100 |
| 李平老师     | 美术   |    100 |
| 李平老师     | 美术   |    100 |
| 李平老师     | 美术   |     88 |
| 李平老师     | 美术   |     88 |
| 李平老师     | 美术   |     22 |
| 李平老师     | 美术   |     87 |
| 李平老师     | 美术   |     87 |
| 李平老师     | 美术   |     87 |
+--------------+--------+--------+
  
13、查询全部学生都选修了的课程号和课程名
    SELECT course_id FROM score
                GROUP BY course_id
                HAVING COUNT(course_id)=(SELECT COUNT(sid) FROM student);
Empty set (0.00 sec)
 
14、查询每门课程被选修的次数
    SELECT cname 课程名称,COUNT(course_id)次数 FROM score LEFT JOIN course on course.cid=score.course_id GROUP BY course_id;
+--------------+--------+
| 课程名称     | 次数   |
+--------------+--------+
| 生物         |     12 |
| 物理         |     11 |
| 体育         |     12 |
| 美术         |     12 |
+--------------+--------+
 
15、查询只选修了一门课程的学生姓名和学号
    SELECT student.sid 学号 ,sname 姓名  FROM score LEFT JOIN student ON student.sid=score.student_id 
            GROUP BY student_id HAVING COUNT(course_id)=1;
+--------+--------+
| 学号   | 姓名   |
+--------+--------+
|     13 | 刘三   |
+--------+--------+
 
16、查询所有学生考出的成绩并按从高到低排序（成绩去重）
    SELECT DISTINCT num 成绩 from score ORDER BY num DESC;
+--------+
| 成绩   |
+--------+
|    100 |
|     99 |
|     91 |
|     90 |
|     88 |
|     87 |
|     79 |
|     77 |
|     68 |
|     67 |
|     66 |
|     43 |
|     22 |
|     11 |
|     10 |
|      9 |
|      8 |
+--------+
 
17、查询平均成绩大于85的学生姓名和平均成绩
    SELECT student.sname 姓名,avg(num) 平均成绩 FROM score LEFT JOIN student ON student.sid=score.student_id 
            GROUP BY student_id  HAVING avg(num) > 85;
+--------+--------------+
| 姓名   | 平均成绩     |
+--------+--------------+
| 刘三   |      87.0000 |
+--------+--------------+
 
18、查询生物成绩不及格的学生姓名和对应生物分数
    SELECT sname 姓名,cname 课程,num 分数 FROM (SELECT student_id,cname,num FROM score LEFT JOIN course on course.cid=score.course_id 
        WHERE cname="生物" and num<60) AS A
        LEFT JOIN 
        student ON A.student_id=student.sid;
+--------+--------+--------+
| 姓名   | 课程   | 分数   |
+--------+--------+--------+
| 理解   | 生物   |     10 |
| 钢蛋   | 生物   |      8 |
| 张四   | 生物   |      9 |
| 铁锤   | 生物   |      9 |
| 李三   | 生物   |      9 |
+--------+--------+--------+
        
19、查询在所有选修了李平老师课程的学生中，这些课程(李平老师的课程，不是所有课程)平均成绩最高的学生姓名
     SELECT sid 学号,sname 学生, tname 老师,平均成绩 from (SELECT student_id,tname,AVG(num) 平均成绩 FROM 
        (SELECT cid,tid,tname FROM course RIGHT JOIN teacher ON teacher.tid=course.teacher_id WHERE tname LIKE "李平%") AS A 
            LEFT  JOIN score ON A.cid=score.course_id GROUP BY student_id ORDER BY AVG(num) DESC LIMIT 1) AS B 
            LEFT JOIN student ON student.sid=B.student_id;
+--------+--------+--------------+--------------+
| 学号   | 学生   | 老师         | 平均成绩     |
+--------+--------+--------------+--------------+
|      6 | 张四   | 李平老师     |     100.0000 |
+--------+--------+--------------+--------------+