目录标题

实验三 DMDBMS表查询操作

实验三 DMDBMS表查询操作

一、实验目的：

1．掌握查询中操作符的应用；
2．掌握对复杂查询的查询要求拆解分析；
3．掌握SQL语言对数据库信息及用户信息进行查询；
4．理解和掌握SQL语言: 能够熟练地使用distinct、AS some_name（别名）、join、group by、order by、having、limit、like相关命令对表数据进行复杂查询。
5．完成对范例数据的复杂查询，包括对表数据的查询、去重、分组、数据限制、连接查询等。

二、实验要求：

1．掌握对复杂查询的查询要求拆解分析
2．掌握查询中操作符的应用
3．熟悉DQL语言中各参数的使用方法及应用场景
4．理解和掌握SQL语言: 能够熟练地使用distinct、AS some_name（别名）、join、group by、order by、having、limit、like相关命令对表数据进行复杂查询。
5．熟悉例题查询思路。

三、实验重点和难点：

实验重点：别名的使用、条件查询、连接查询、子查询、数据分组、数据排序
实验难点：连接查询、子查询、分组查询、函数的使用

四、实验内容：

数据库信息、用户信息查询
表数据查询
2.1．去重查询
2.2. 查询列的选择
2.3．别名的使用
2.4. 条件查询
2.5. 连接查询
2.6. 子查询
2.7. 数据分组
2.8.数据排序
2.9.数据限制

五、实验步骤与结果：

说明：每一部分实验内容，请描述实验过程，并搭配实验结果截图

1. 表创建

//截图SQL指令及输入结果

数据准备：
创建Stuinfo、Sco、Student、Teacher、Course、Score表，并根据实际情况合理的定义主键、联合主键、外键以及相关约束。
表结构如下：
1、Stuinfo

2、Sco

3、Student

4、Teacher

5、Course

6、Score

create table Stuinfo(
	SSNO INT NOT NULL,
	SNAME VARCHAR(20) DEFAULT NULL,
	SAGE INT DEFAULT NULL,
	PRIMARY KEY(SSNO)
);

create table Sco(
	SNO INT ,
	CNO INT DEFAULT NULL,
	DEGREE INT DEFAULT NULL,
	FOREIGN KEY(SNO) REFERENCES Stuinfo(SSNO)
);

create TABLE Student(
	SNO VARCHAR(20) NOT NULL,
	SNAME VARCHAR(20) NOT NULL,
	SSEX VARCHAR(20) NOT NULL,
	SBIRTH DATETIME(6),
	CLASS VARCHAR(20),
	PRIMARY KEY(SNO)
);

create TABLE Teacher(
	TNO VARCHAR(20) NOT NULL,
	TNAME VARCHAR(20) NOT NULL,
	TSEX VARCHAR(20) NOT NULL,
	TBIR DATETIME(6),
	PROF VARCHAR(20),
	DEPART VARCHAR(20) NOT NULL,
	PRIMARY KEY(TNO)
);

create table Course(
	CNO VARCHAR(20) NOT NULL,
	CNAME VARCHAR(20) NOT NULL,
	TNO VARCHAR(20) NOT NULL,
	PRIMARY KEY(CNO),
	FOREIGN KEY(TNO) REFERENCES Teacher(TNO)
);

create table Score(
	SNO VARCHAR(20) NOT NULL,
	CNO VARCHAR(20) NOT NULL,
	DEGREE DECIMAL, 
	FOREIGN KEY(CNO) REFERENCES Course(CNO),
	FOREIGN KEY(SNO) REFERENCES Student(SNO)
);

2. 数据填充

//截图SQL指令及输入结果
按照如下信息，将数据插入到对应表中，若无法插入请说明原因
Stuinfo：
1001,aa,12
1002,bb,16
1003,cc,14
1004,dd,14
1005,ee,15

insert INTO EXP3.STUINFO(SSNO,SNAME,SAGE) VALUES (1001,'aa',12);
insert INTO EXP3.STUINFO(SSNO,SNAME,SAGE) VALUES (1002,'bb',13);
insert INTO EXP3.STUINFO(SSNO,SNAME,SAGE) VALUES (1003,'cc',14);
insert INTO EXP3.STUINFO(SSNO,SNAME,SAGE) VALUES (1004,'dd',15);
insert INTO EXP3.STUINFO(SSNO,SNAME,SAGE) VALUES (1005,'ee',16);

Sco：
1001,2003,60
1002,2003,53
1003,2003,48
1003,2004,85
1004,2004,96
1005,2003,88
1006,2004,77

insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1001,2003,60);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1002,2003,53);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1003,2003,48);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1003,2004,85);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1004,2004,96);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1005,2003,88);
insert INTO EXP3.Sco(SNO,CNO,DEGREE) VALUES (1006,2004,77);

第七句产生问题：违反外键约束

Student：
101,朱超,男,1997-09-01,95033
102,刘法治,男,1998-10-02,95031
103,成文彬,女,1997-01-01,95033
104,罗聪,男,1996-11-01,95033
105,董俊杰,女,1975-02-01,95031
106,李衡,女,1998-06-01,95031

insert INTO EXP3.Student VALUES ('101','朱超','男','1997-09-01','95033');
insert INTO EXP3.Student VALUES ('102','刘法治','男','1998-10-02','95031');
insert INTO EXP3.Student VALUES ('103','成文彬','女','1997-01-01','95033');
insert INTO EXP3.Student VALUES ('104','罗聪','男','1996-11-01','95033');
insert INTO EXP3.Student VALUES ('105','董俊杰','女','1975-02-01','95031');
insert INTO EXP3.Student VALUES ('106','李衡','女','1998-06-01','95031');

Teacher：
804,李,男,1985-12-02,副教授,计算机系
805,王,女,1975-10-02,助教,计算机系
806,张,男,1995-11-02,教授,电子工程
807,吴,女,1997-1-02,讲师,计算机系

insert INTO EXP3.Teacher VALUES ('804','李','男','1985-12-02','副教授','计算机系');
insert INTO EXP3.Teacher VALUES ('805','王','女','1975-10-02','助教','计算机系');
insert INTO EXP3.Teacher VALUES ('806','张','男','1995-11-02','教授','电子工程');
insert INTO EXP3.Teacher VALUES ('807','吴','女','1997-1-02','讲师','计算机系');

Course：
3-106,高等数学,804
3-105,C语言,805
4-107,操作系统,806
5-108,大数据,807

insert INTO EXP3.Course VALUES ('3-106','高等数学','804');
insert INTO EXP3.Course VALUES ('3-105','C语言','805');
insert INTO EXP3.Course VALUES ('4-107','操作系统','806');
insert INTO EXP3.Course VALUES ('5-108','大数据','807');

Score：
103,3-106,80
103,3-105,85
104,3-106,64
104,4-107,91
105,5-108,78
105,3-106,65
105,3-105,67
106,3-106,87
106,4-107,56
107,5-108,76
107,4-107,87
108,5-108,98

insert INTO EXP3.Score VALUES ('103','3-106',80);
insert INTO EXP3.Score VALUES ('103','3-105',85);
insert INTO EXP3.Score VALUES ('104','3-106',64);
insert INTO EXP3.Score VALUES ('104','4-107',91);
insert INTO EXP3.Score VALUES ('105','5-108',78);
insert INTO EXP3.Score VALUES ('105','3-106',65);
insert INTO EXP3.Score VALUES ('105','3-105',67);
insert INTO EXP3.Score VALUES ('106','3-106',87);
insert INTO EXP3.Score VALUES ('106','4-107',56);
insert INTO EXP3.Score VALUES ('107','5-108',76);
insert INTO EXP3.Score VALUES ('107','4-107',87);
insert INTO EXP3.Score VALUES ('108','5-108',98);

句10，11，12错误：违反外键约束

3. 数据查询

//截图SQL指令及输入结果

3.1查出选修了2003这门课(sco)，不及格的同学的名字(stuinfo)

select SNAME FROM EXP3.STUINFO WHERE 
	SSNO in (select SNO FROM EXP3.SCO WHERE
		 	(SCO.CNO = 2003 AND SCO.DEGREE < 60));

3.2查出选修了2003这门课不及格的（sco），但是2004这门课及格了的学生的姓名（stuinfo）

select SNAME FROM EXP3.STUINFO WHERE 
	SSNO in (select SNO FROM EXP3.SCO WHERE
		SNO IN
		 	(SELECT SNO FROM EXP3.SCO WHERE SCO.CNO = 2003 AND SCO.DEGREE < 60 ) AND  (SELECT SNO WHERE 
		 		(
		 			SCO.CNO = 2004 AND SCO.DEGREE >= 60
		 		))
		 	);

下列查询涉及的表均为Student、Teacher、Course、Score

3.3查询教师所有的专业及不重复的depart列

select PROF FROM EXP3.TEACHER;

select DISTINCT DEPART FROM EXP3.TEACHER;

3.4查询score表中成绩在60-80之间的所有记录

select * FROM EXP3.SCORE WHERE SCORE.DEGREE BETWEEN 60 AND 80;

3.5查询score表中成绩为85，67或87的记录

select * FROM EXP3.SCORE WHERE SCORE.DEGREE IN (85,67,87);

3.6查询student表中95031班，或性别为女的同学的记录

select * FROM EXP3.STUDENT WHERE STUDENT.CLASS = '95031' OR STUDENT.SSEX = '女';

3.7以class降序查询student表的所有记录

select * FROM EXP3.STUDENT ORDER BY STUDENT.CLASS DESC ;

3.8查询95031班的学生人数

select COUNT(CLASS) FROM EXP3.STUDENT WHERE STUDENT.CLASS='95031';

3.9查询score表中最高分的学生学号和课程号

select SNO,CNO FROM EXP3.SCORE WHERE SCORE.DEGREE in (SELECT MAX(SCORE.DEGREE) FROM EXP3.SCORE) ;

3.10查询每门课的平均分

SELECT SCORE.CNO,AVG(DEGREE) AS AVG FROM EXP3.SCORE GROUP BY SCORE.CNO;

3.11查询score表中至少有两名学生选修的并以3开头的课

SELECT DISTINCT CNO FROM EXP3.SCORE WHERE
 	CNO IN( 
		SELECT CNO FROM(
 			SELECT CNO,COUNT(SCORE.CNO)as CNT FROM EXP3.SCORE GROUP BY SCORE.CNO) WHERE CNT >= 2)
 	AND CNO LIKE '3%';

3.12查询所有学生的sname,cno和degree列

select SNAME,CNO,DEGREE FROM STUDENT INNER JOIN EXP3.SCORE ON STUDENT.SNO=SCORE.SNO;

3.13查询所有学生的sname,cname和degree列

select SNAME,CNAME,DEGREE FROM STUDENT 
	INNER JOIN EXP3.SCORE ON STUDENT.SNO=SCORE.SNO 
	INNER JOIN EXP3.COURSE ON SCORE.CNO = COURSE.CNO;

3.14查询95031班学生每门课的平均分

select CNAME,AVG(DEGREE)AS AVG FROM ( SELECT SNAME,CNAME,DEGREE FROM STUDENT
	INNER JOIN EXP3.SCORE ON STUDENT.SNO = SCORE.SNO 
	INNER JOIN EXP3.COURSE ON SCORE.CNO = COURSE.CNO
	WHERE STUDENT.CLASS = '95031')GROUP BY CNAME;

3.15查询选修‘3-105’课程的成绩高于105号学生的’3-105’课程成绩的所有同学的记录

SELECT * FROM EXP3.SCORE WHERE 
	SCORE.CNO = '3-105' 
	AND 
	SCORE.DEGREE > (select MAX(DEGREE) FROM (select DEGREE FROM EXP3.SCORE WHERE SCORE.CNO='3-105' AND SCORE.SNO='105'));

3.16查询成绩高于学号为‘109’，课程号为’3-105’的成绩的所有记录

SELECT * FROM EXP3.SCORE WHERE 
SCORE.DEGREE > (select MAX(DEGREE) FROM (select DEGREE FROM EXP3.SCORE WHERE SCORE.CNO='3-105' AND SCORE.SNO='109'));

3.17查询吴教师任课的学生成绩

select SNAME,COURSE.CNO,CNAME,DEGREE FROM STUDENT 
	INNER JOIN EXP3.SCORE ON STUDENT.SNO=SCORE.SNO 
	INNER JOIN EXP3.COURSE ON SCORE.CNO = COURSE.CNO
	INNER JOIN EXP3.TEACHER ON COURSE.TNO = TEACHER.TNO
	WHERE TEACHER.TNAME = '吴';

#### 3.18查询选修某门课程的同学人数大于2人的教师的名字
SELECT DISTINCT TT FROM (
 SELECT SCORE.CNO AS SC,TEACHER.TNAME AS TT FROM (EXP3.SCORE 
	INNER JOIN EXP3.COURSE ON SCORE.CNO=COURSE.CNO
	INNER JOIN EXP3.TEACHER ON COURSE.TNO = TEACHER.TNO))
 WHERE TT IN (
 	SELECT TT FROM (
 		SELECT TT,COUNT(SC) AS CNT FROM (
 			SELECT SCORE.CNO AS SC,TEACHER.TNAME AS TT FROM (EXP3.SCORE 
			INNER JOIN EXP3.COURSE ON SCORE.CNO=COURSE.CNO
			INNER JOIN EXP3.TEACHER ON COURSE.TNO = TEACHER.TNO))
		GROUP BY SC
 	)WHERE CNT >=2
 )

3.19查询选修课程为3-105，且成绩高于选修编号为3-106课程的同学的cno,sno和degree

select CNO,SNO,DEGREE from EXP3.SCORE WHERE 
	CNO='3-105' 
 AND 
 	DEGREE > all(SELECT DEGREE FROM SCORE where SCORE.CNO='3-106');

3.20查询student表中不姓‘成’的同学的记录

SELECT * FROM EXP3.STUDENT WHERE NOT STUDENT.SNAME LIKE '成';

3.21查询男教师及其所上的课程

select TEACHER.TNO,TNAME,COURSE.CNO,CNAME FROM EXP3.TEACHER
INNER JOIN EXP3.COURSE ON COURSE.TNO = TEACHER.TNO
WHERE TEACHER.TSEX= '男';

达梦数据库实验三：DMDBMS表查询操作