MySQL硬核操作练习题

导出现有数据库数据：

mysqldump -u用户名 -p密码数据库名称 >导出文件路径 # 结构+数据
mysqldump -u用户名 -p密码 -d 数据库名称 >导出文件路径 # 结构
！！！注意：（）一定要用英文半角

  1 /*
  2  Navicat Premium Data Transfer
  3 
  4  Source Server         : localhost
  5  Source Server Type    : MySQL
  6  Source Server Version : 50624
  7  Source Host           : localhost
  8  Source Database       : sqlexam
  9 
 10  Target Server Type    : MySQL
 11  Target Server Version : 50624
 12  File Encoding         : utf-8
 13 
 14  Date: 10/21/2016 06:46:46 AM
 15 */
 16 
 17 SET NAMES utf8;
 18 SET FOREIGN_KEY_CHECKS = 0;
 19 
 20 -- ----------------------------
 21 --  Table structure for `class`
 22 -- ----------------------------
 23 DROP TABLE IF EXISTS `class`;
 24 CREATE TABLE `class` (
 25   `cid` int(11) NOT NULL AUTO_INCREMENT,
 26   `caption` varchar(32) NOT NULL,
 27   PRIMARY KEY (`cid`)
 28 ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
 29 
 30 -- ----------------------------
 31 --  Records of `class`
 32 -- ----------------------------
 33 BEGIN;
 34 INSERT INTO `class` VALUES ('1', '三年二班'), ('2', '三年三班'), ('3', '一年二班'), ('4', '二年九班');
 35 COMMIT;
 36 
 37 -- ----------------------------
 38 --  Table structure for `course`
 39 -- ----------------------------
 40 DROP TABLE IF EXISTS `course`;
 41 CREATE TABLE `course` (
 42   `cid` int(11) NOT NULL AUTO_INCREMENT,
 43   `cname` varchar(32) NOT NULL,
 44   `teacher_id` int(11) NOT NULL,
 45   PRIMARY KEY (`cid`),
 46   KEY `fk_course_teacher` (`teacher_id`),
 47   CONSTRAINT `fk_course_teacher` FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`tid`)
 48 ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
 49 
 50 -- ----------------------------
 51 --  Records of `course`
 52 -- ----------------------------
 53 BEGIN;
 54 INSERT INTO `course` VALUES ('1', '生物', '1'), ('2', '物理', '2'), ('3', '体育', '3'), ('4', '美术', '2');
 55 COMMIT;
 56 
 57 -- ----------------------------
 58 --  Table structure for `score`
 59 -- ----------------------------
 60 DROP TABLE IF EXISTS `score`;
 61 CREATE TABLE `score` (
 62   `sid` int(11) NOT NULL AUTO_INCREMENT,
 63   `student_id` int(11) NOT NULL,
 64   `course_id` int(11) NOT NULL,
 65   `num` int(11) NOT NULL,
 66   PRIMARY KEY (`sid`),
 67   KEY `fk_score_student` (`student_id`),
 68   KEY `fk_score_course` (`course_id`),
 69   CONSTRAINT `fk_score_course` FOREIGN KEY (`course_id`) REFERENCES `course` (`cid`),
 70   CONSTRAINT `fk_score_student` FOREIGN KEY (`student_id`) REFERENCES `student` (`sid`)
 71 ) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=utf8;
 72 
 73 -- ----------------------------
 74 --  Records of `score`
 75 -- ----------------------------
 76 BEGIN;
 77 INSERT INTO `score` VALUES ('1', '1', '1', '10'), ('2', '1', '2', '9'), ('5', '1', '4', '66'), ('6', '2', '1', '8'), ('8', '2', '3', '68'), ('9', '2', '4', '99'), ('10', '3', '1', '77'), ('11', '3', '2', '66'), ('12', '3', '3', '87'), ('13', '3', '4', '99'), ('14', '4', '1', '79'), ('15', '4', '2', '11'), ('16', '4', '3', '67'), ('17', '4', '4', '100'), ('18', '5', '1', '79'), ('19', '5', '2', '11'), ('20', '5', '3', '67'), ('21', '5', '4', '100'), ('22', '6', '1', '9'), ('23', '6', '2', '100'), ('24', '6', '3', '67'), ('25', '6', '4', '100'), ('26', '7', '1', '9'), ('27', '7', '2', '100'), ('28', '7', '3', '67'), ('29', '7', '4', '88'), ('30', '8', '1', '9'), ('31', '8', '2', '100'), ('32', '8', '3', '67'), ('33', '8', '4', '88'), ('34', '9', '1', '91'), ('35', '9', '2', '88'), ('36', '9', '3', '67'), ('37', '9', '4', '22'), ('38', '10', '1', '90'), ('39', '10', '2', '77'), ('40', '10', '3', '43'), ('41', '10', '4', '87'), ('42', '11', '1', '90'), ('43', '11', '2', '77'), ('44', '11', '3', '43'), ('45', '11', '4', '87'), ('46', '12', '1', '90'), ('47', '12', '2', '77'), ('48', '12', '3', '43'), ('49', '12', '4', '87'), ('52', '13', '3', '87');
 78 COMMIT;
 79 
 80 -- ----------------------------
 81 --  Table structure for `student`
 82 -- ----------------------------
 83 DROP TABLE IF EXISTS `student`;
 84 CREATE TABLE `student` (
 85   `sid` int(11) NOT NULL AUTO_INCREMENT,
 86   `gender` char(1) NOT NULL,
 87   `class_id` int(11) NOT NULL,
 88   `sname` varchar(32) NOT NULL,
 89   PRIMARY KEY (`sid`),
 90   KEY `fk_class` (`class_id`),
 91   CONSTRAINT `fk_class` FOREIGN KEY (`class_id`) REFERENCES `class` (`cid`)
 92 ) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;
 93 
 94 -- ----------------------------
 95 --  Records of `student`
 96 -- ----------------------------
 97 BEGIN;
 98 INSERT INTO `student` VALUES ('1', '男', '1', '理解'), ('2', '女', '1', '钢蛋'), ('3', '男', '1', '张三'), ('4', '男', '1', '张一'), ('5', '女', '1', '张二'), ('6', '男', '1', '张四'), ('7', '女', '2', '铁锤'), ('8', '男', '2', '李三'), ('9', '男', '2', '李一'), ('10', '女', '2', '李二'), ('11', '男', '2', '李四'), ('12', '女', '3', '如花'), ('13', '男', '3', '刘三'), ('14', '男', '3', '刘一'), ('15', '女', '3', '刘二'), ('16', '男', '3', '刘四');
 99 COMMIT;
100 
101 -- ----------------------------
102 --  Table structure for `teacher`
103 -- ----------------------------
104 DROP TABLE IF EXISTS `teacher`;
105 CREATE TABLE `teacher` (
106   `tid` int(11) NOT NULL AUTO_INCREMENT,
107   `tname` varchar(32) NOT NULL,
108   PRIMARY KEY (`tid`)
109 ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
110 
111 -- ----------------------------
112 --  Records of `teacher`
113 -- ----------------------------
114 BEGIN;
115 INSERT INTO `teacher` VALUES ('1', '张磊老师'), ('2', '李平老师'), ('3', '刘海燕老师'), ('4', '朱云海老师'), ('5', '李杰老师');
116 COMMIT;
117 
118 SET FOREIGN_KEY_CHECKS = 1;
119 
120 表结构和数据

导入示例数据库数据

 1 思路：
 2 
 3     获取所有有生物课程的人（学号，成绩） - 临时表
 4 
 5     获取所有有物理课程的人（学号，成绩） - 临时表
 6 
 7     根据【学号】连接两个临时表：
 8 
 9    
10         select A.student_id,sw,ty from
11 
12  
13 
14         (select student_id,num as sw from score left join course on score.course_id = course.cid where course.cname = '生物') as A
15 
16  
17 
18         left join
19 
20  
21 
22         (select student_id,num  as ty from score left join course on score.course_id = course.cid where course.cname = '体育') as B
23 
24  
25 
26         on A.student_id = B.student_id where sw > if(isnull(ty),0,ty);

2、查询“生物”课程比“物理”课程成绩高的所有学生的学号；

1 思路：
2         根据学生分组，使用avg获取平均值，通过having对avg进行筛选
3 select student_id,avg(num) from score group by student_id having avg(num) > 60

3、查询平均成绩大于60分的同学的学号和平均成绩；

1 SELECT
2     count( course_id ),
3     sum( num ),
4     student_id 
5 FROM
6     score
7     LEFT JOIN student ON score.student_id = student.sid 
8 GROUP BY
9     student_id

4、查询所有同学的学号、姓名、选课数、总成绩；

1 select count(tid) from teacher where tname like "李%"

5、查询姓“李”的老师的个数；

 思路：
        先查到“李平老师”老师教的所有课ID
        获取选过课的所有学生ID
        学生表中筛选

SELECT
    sid,
    sname 
FROM
    student 
WHERE
    sid NOT IN (
    SELECT DISTINCT
        student_id 
    FROM
        score 
WHERE
    course_id IN ( SELECT cid FROM course LEFT JOIN teacher ON course.teacher_id = teacher.tid WHERE tname = "李平老师" ))

6、查询没学过“李平”老师课的同学的学号、姓名；

 1   思路：
 2         先查到既选择001又选择002课程的所有同学
 3         根据学生进行分组，如果学生数量等于2表示，两门均已选择
 4 
 5 
 6 
 7 
 8  select student_id,sname from
 9  
10  (select student_id,course_id from score where course_id = 1 or course_id = 2) as B     
11  left join student on B.student_id = student.sid group by student_id HAVING count(student_id) > 1

7、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；

 1 SELECT
 2 sid,sname
 3 FROM
 4     (
 5     SELECT
 6         score.student_id 
 7     FROM
 8         ( SELECT cid FROM course LEFT JOIN teacher ON course.teacher_id = teacher.tid WHERE tname = '李平老师' ) AS A
 9         LEFT JOIN score ON A.cid = score.course_id 
10     ) AS B
11     LEFT JOIN student ON B.student_id = student.sid

8、查询学过“叶平”老师所教的所有课的同学的学号、姓名；

思路：先找学过课程1和课程2的学生



SELECT
    D.sid1,
    student.sname 
FROM
    (
    SELECT
        sid1 
    FROM
        (
        SELECT
            A.student_id AS sid1,
            B.student_id AS sid2,
            A.num AS num1,
            B.num AS num2 
        FROM
            ( SELECT * FROM score WHERE course_id = 1 ) AS A
            INNER JOIN ( SELECT * FROM score WHERE course_id = 2 ) AS B ON A.student_id = B.student_id 
        ) AS C 
    WHERE
        C.num1 > C.num2 
    ) AS D
    LEFT JOIN student ON D.sid1 = student.sid

9、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名；

posted @ 2020-03-13 13:31 爬爬QQ 阅读(160) 评论(0) 收藏举报

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MySQL硬核操作练习题

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