MySQL 查询语句练习2

创建表

/*

Navicat MySQL Data Transfer

Source Server         : localhost_3306

Source Server Version : 50719

Source Host           : localhost:3306

Source Database       : oldbo

Target Server Type    : MYSQL

Target Server Version : 50719

File Encoding         : 65001

Date: 2017-07-26 15:46:16

*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------

-- Table structure for class

-- ----------------------------

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 ('', '三年二班');

INSERT INTO `class` VALUES ('', '三年三班');

INSERT INTO `class` VALUES ('', '一年二班');

INSERT INTO `class` VALUES ('', '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 ('', '生物', '');

INSERT INTO `course` VALUES ('', '物理', '');

INSERT INTO `course` VALUES ('', '体育', '');

INSERT INTO `course` VALUES ('', '美术', '');

-- ----------------------------

-- 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 ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

INSERT INTO `score` VALUES ('', '', '', '');

-- ----------------------------

-- 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 ('', '男', '', '理解');

INSERT INTO `student` VALUES ('', '女', '', '钢蛋');

INSERT INTO `student` VALUES ('', '男', '', '张三');

INSERT INTO `student` VALUES ('', '男', '', '张一');

INSERT INTO `student` VALUES ('', '女', '', '张二');

INSERT INTO `student` VALUES ('', '男', '', '张四');

INSERT INTO `student` VALUES ('', '女', '', '铁锤');

INSERT INTO `student` VALUES ('', '男', '', '李三');

INSERT INTO `student` VALUES ('', '男', '', '李一');

INSERT INTO `student` VALUES ('', '女', '', '李二');

INSERT INTO `student` VALUES ('', '男', '', '李四');

INSERT INTO `student` VALUES ('', '女', '', '如花');

INSERT INTO `student` VALUES ('', '男', '', '刘三');

INSERT INTO `student` VALUES ('', '男', '', '刘一');

INSERT INTO `student` VALUES ('', '女', '', '刘二');

INSERT INTO `student` VALUES ('', '男', '', '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 ('', '张磊老师');

INSERT INTO `teacher` VALUES ('', '李平老师');

INSERT INTO `teacher` VALUES ('', '刘海燕老师');

INSERT INTO `teacher` VALUES ('', '朱云海老师');

INSERT INTO `teacher` VALUES ('', '李杰老师');

SET FOREIGN_KEY_CHECKS=1;

1、将所有的课程的名称以及对应的任课老师姓名打印出来，如下：

mysql> SELECT cname,tname FROM course LEFT JOIN teacher ON course.`teacher_id`=teacher.`tid`;

+--------+-----------------+

| cname | tname |

+--------+-----------------+

| 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 |

+--------+-----------------+

4 rows in set (0.00 sec)

2、查询学生表中男女生各有多少人？如下：

mysql> SELECT gender,COUNT(sid) FROM student GROUP BY gender;

+--------+------------+

| gender | COUNT(sid) |

+--------+------------+

| 女 | 6 |

| 男 | 10 |

+--------+------------+

2 rows in set (0.00 sec)

3、查询物理成绩等于100的学生的姓名？如下：

mysql> SELECT sname FROM student WHERE sid IN(SELECT student_id FROM score WHERE course_id=2 AND num=100);

+--------+

| sname  |

+--------+

| 张四   |

| 铁锤   |

| 李三   |

+--------+

3 rows in set (0.00 sec)

4、查询平均成绩大于八十分的同学的姓名和平均成绩，如下：

mysql> SELECT sname AS '姓名',avgnum AS '平均分' FROM student INNER JOIN (SELECT student_id,AVG(num)AS avgnum FROM score GROUP BY student_id HAVING AVG(num)>80)AS id_avgnum ON student.`sid`=id_avgnum.student_id;

+--------+-----------+

| 姓名   | 平均分    |

+--------+-----------+

| 张三   |   82.2500 |

| 刘三   |   87.0000 |

+--------+-----------+

2 rows in set (0.00 sec)

mysql> SELECT sname,AVG(num) FROM student INNER JOIN score ON student.`sid`=score.`student_id` GROUP BY student_id HAVING AVG(num)>80;

+--------+----------+

| sname  | AVG(num) |

+--------+----------+

| 张三   |  82.2500 |

| 刘三   |  87.0000 |

+--------+----------+

2 rows in set (0.01 sec)

5、查询所有学生的学号，姓名，选课数，总成绩

mysql> SELECT student.sid,sname,SUM(num),COUNT(course_id) FROM student INNER JOIN score ON student.`sid`=score.`student_id` GROUP BY student_id;

+-----+--------+----------+------------------+

| sid | sname | SUM(num) | COUNT(course_id) |

+-----+--------+----------+------------------+

| 1 | 理解 | 85 | 3 |

| 2 | 钢蛋 | 175 | 3 |

| 3 | 张三 | 329 | 4 |

| 4 | 张一 | 257 | 4 |

| 5 | 张二 | 257 | 4 |

| 6 | 张四 | 276 | 4 |

| 7 | 铁锤 | 264 | 4 |

| 8 | 李三 | 264 | 4 |

| 9 | 李一 | 268 | 4 |

| 10 | 李二 | 297 | 4 |

| 11 | 李四 | 297 | 4 |

| 12 | 如花 | 297 | 4 |

| 13 | 刘三 | 87 | 1 |

+-----+--------+----------+------------------+

13 rows in set (0.00 sec)

6、查询姓李老师的个数

mysql> SELECT COUNT(tid) FROM teacher WHERE tname LIKE '李%';

+------------+

| COUNT(tid) |

+------------+

| 2 |

+------------+

1 row in set (0.00 sec)

7、查询没有报李平老师课的学生姓名

mysql> SELECT sname FROM student WHERE sid NOT IN(SELECT student_id FROM score WHERE course_id IN(SELECT cid FROM course WHERE teacher_id=(SELECT tid FROM teacher WHERE tname='李平老师')));

+--------+

| sname |

+--------+

| 刘三 |

| 刘一 |

| 刘二 |

| 刘四 |

+--------+

4 rows in set (0.00 sec)

8、查询物理课程比生物课程高的学生的学号

SELECT A.student_id,A.num,b.num FROM

(SELECT * FROM score WHERE course_id=(SELECT cid FROM course WHERE cname="物理"))as A

INNER JOIN

(SELECT * FROM score WHERE course_id=(SELECT cid FROM course WHERE cname="生物"))as B

ON

A.student_id=B.student_id

WHERE A.num>B.num

9、查询没有同时选修物理课程和体育课程的学生姓名

SELECT sname FROM student WHERE sid NOT in (SELECT student_id FROM score

WHERE course_id in (SELECT cid FROM course WHERE cname="物理" OR cname="体育")

GROUP BY student_id HAVING COUNT(sid)=2)

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 student LEFT JOIN class ON student.class_id=class.cid

where sid in (SELECT student_id FROM score WHERE num<60

GROUP BY student_id HAVING COUNT(sid)>1)

11 、查询选修了所有课程的学生姓名

SELECT sname FROM student WHERE sid in (SELECT student_id FROM score

GROUP BY student_id HAVING COUNT(sid)!=(SELECT COUNT(cid) FROM course))

12、查询李平老师教的课程的所有成绩记录

SELECT * FROM score WHERE course_id in (SELECT cid FROM course LEFT JOIN teacher ON teacher.tid=course.teacher_id

WHERE tname="李平老师")

13、查询全部学生都选修了的课程号和课程名
无

14、查询每门课程被选修的次数

mysql> SELECT course.cname,COUNT(score.course_id) FROM course INNER JOIN score ON course.cid=score.course_id GROUP BY score.course_id;

+--------+------------------------+

| cname | COUNT(score.course_id) |

+--------+------------------------+

| 生物 | 12 |

| 物理 | 11 |

| 体育 | 12 |

| 美术 | 12 |

+--------+------------------------+

4 rows in set (0.00 sec)

15、查询之选修了一门课程的学生姓名和学号

mysql> SELECT student_id,student.sname,COUNT(course_id) FROM student INNER JOIN score ON student.`sid`=score.`student_id` GROUP BY student_id HAVING COUNT(course_id)=1;

+------------+--------+------------------+

| student_id | sname | COUNT(course_id) |

+------------+--------+------------------+

| 13 | 刘三 | 1 |

+------------+--------+------------------+

1 row in set (0.00 sec)

16、查询所有学生考出的成绩并按从高到低排序（成绩去重）

mysql> select distinct num from score order by num desc;

+-----+

| num |

+-----+

| 100 |

| 99 |

| 91 |

| 90 |

| 88 |

| 87 |

| 79 |

| 77 |

| 68 |

| 67 |

| 66 |

| 43 |

| 22 |

| 11 |

| 10 |

| 9 |

| 8 |

+-----+

17 rows in set (0.00 sec)

17、查询平均成绩大于85的学生姓名和平均成绩

mysql> SELECT sname,AVG(num) FROM student INNER JOIN score ON student.`sid`=score.`student_id` GROUP BY student_id HAVING AVG(num)>85;

+--------+----------+

| sname | AVG(num) |

+--------+----------+

| 刘三 | 87.0000 |

+--------+----------+

1 row in set (0.00 sec)

18、查询生物成绩不及格的学生姓名和对应生物分数

mysql> SELECT student.`sname`,A.num FROM student INNER JOIN (SELECT student_id,num FROM score WHERE num<60 AND course_id=(SELECT cid FROM course WHERE cname='生物'))AS A ON student.sid=A.student_id;

+--------+-----+

| sname | num |

+--------+-----+

| 理解 | 10 |

| 钢蛋 | 8 |

| 张四 | 9 |

| 铁锤 | 9 |

| 李三 | 9 |

+--------+-----+

5 rows in set (0.00 sec)

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

mysql> SELECT sname FROM student INNER JOIN (SELECT student_id,SUM(num) FROM (SELECT * FROM score WHERE course_id IN(SELECT cid FROM course WHERE teacher_id=(SELECT tid FROM teacher WHERE tname='李平老师')))AS aa GROUP BY student_id DESC LIMIT 1)AS bb ON student.sid=bb.student_id;

+--------+

| sname |

+--------+

| 如花 |

+--------+

1 row in set (0.00 sec)

20、查询每门课程成绩最好的前两名学生姓名(答案非准确)

mysql> SELECT student.`sname`,ee.course_id,ee.num FROM student INNER JOIN

-> (SELECT * FROM (SELECT student_id,course_id,num FROM score WHERE course_id=1 ORDER BY num DESC LIMIT 2)AS aa

-> UNION ALL SELECT * FROM (SELECT student_id,course_id,num FROM score WHERE course_id=2 ORDER BY num DESC LIMIT 2)AS bb

-> UNION ALL SELECT * FROM (SELECT student_id,course_id,num FROM score WHERE course_id=3 ORDER BY num DESC LIMIT 2)AS cc

-> UNION ALL SELECT * FROM (SELECT student_id,course_id,num FROM score WHERE course_id=4 ORDER BY num DESC LIMIT 2)AS dd)AS ee

-> ON student.sid=ee.student_id;

+--------+-----------+-----+

| sname | course_id | num |

+--------+-----------+-----+

| 李一 | 1 | 91 |

| 如花 | 1 | 90 |

| 张四 | 2 | 100 |

| 铁锤 | 2 | 100 |

| 张三 | 3 | 87 |

| 刘三 | 3 | 87 |

| 张一 | 4 | 100 |

| 张二 | 4 | 100 |

+--------+-----------+-----+

8 rows in set (0.01 sec)

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