数据库sql语句练习

一、设有一数据库，包括四个表：学生表（Student）、课程表（Course）、成绩表（Score）以及教师信息表（Teacher）。四个表的结构分别如表1-1的表（一）~表（四）所示，数据如表1-2的表（一）~表（四）所示。用SQL语句创建四个表并完成相关题目。

表1-1数据库的表结构

表（一）Student

属性名	数据类型	可否为空	含义
Sno	Char(3)	否	学号（主码）
Sname	Char(8)	否	学生姓名
Ssex	Char(2)	否	学生性别
Sbirthday	datetime	可	学生出生年月
Class	Char(5)	可	学生所在班级

表（二）Course

属性名	数据类型	可否为空	含义
Cno	Char(5)	否	课程号（主码）
Cname	Varchar(10)	否	课程名称
Tno	Char(3)	否	教工编号（外码）

表（三）Score

属性名	数据类型	可否为空	含义
Sno	Char(3)	否	学号（外码）
Cno	Char(5)	否	课程号（外码）
Degree	Decimal(4,1)	可	成绩
主码：Sno+ Cno

表（四）Teacher

属性名	数据类型	可否为空	含义
Tno	Char(3)	否	教工编号（主码）
Tname	Char(4)	否	教工姓名
Tsex	Char(2)	否	教工性别
Tbirthday	datetime	可	教工出生年月
Prof	Char(6)	可	职称
Depart	Varchar(10)	否	教工所在部门

表1-2数据库中的数据

表（一）Student

Sno	Sname	Ssex	Sbirthday	class
108	曾华	男	1977-09-01	95033
105	匡明	男	1975-10-02	95031
107	王丽	女	1976-01-23	95033
101	李军	男	1976-02-20	95033
109	王芳	女	1975-02-10	95031
103	陆君	男	1974-06-03	95031

表（二）Course

Cno	Cname	Tno
3-105	计算机导论	825
3-245	操作系统	804
6-166	数字电路	856
9-888	高等数学	831

表（三）Score

Sno	Cno	Degree
103	3-245	86
105	3-245	75
109	3-245	68
103	3-105	92
105	3-105	88
109	3-105	76
101	3-105	64
107	3-105	91
108	3-105	78
101	6-166	85
107	6-166	79
108	6-166	81

表（四）Teacher

Tno	Tname	Tsex	Tbirthday	Prof	Depart
804	李诚	男	1958-12-02	副教授	计算机系
856	张旭	男	1969-03-12	讲师	电子工程系
825	王萍	女	1972-05-05	助教	计算机系
831	刘冰	女	1977-08-14	助教	电子工程系

--创建一个数据库
create database stuDB
--默认属于primary文件组
on primary
--主数据文件逻辑名称
(name = 'stuDB_data',
--主数据文件物理名称
filename = 'C:\stuDB_data.mdf',
--主数据文件初始大小
size = 3mb,
--主数据文件增长大小
filegrowth = 10%
)
--日志文件
log on
(name = 'stuDB_log',
filename = 'C:\stuDB_log.ldf',
size = 1mb,
filegrowth = 1mb
)

--创建一个学生表
create table Student
(Sno char(3) not null primary key,
Sname char(8) not null,Ssex char(2) not null,
Sbirthday datetime,Class char(5)
)

--创建一个课程表(必须先创建一个Teacher表，否则外键无法建立)
create table Course
(Cno char(5) not null,Cname varchar(10) not null,Tno char(3)not null,
primary key(Cno),
foreign key (Tno) references Teacher(Tno)
)

--创建一个成绩表
create table Score
(Sno char(3) not null,Cno char(5) not null,Degree Decimal(4,1),
primary key (Sno,Cno),
foreign key (Sno) references Student(Sno),
foreign key (Cno) references Course(Cno)
)

--创建一个教师表
create table Teacher
(Tno char(3) not null,Tname char(4) not null,
Tsex char(2) not null,Tbirthday datetime,
Prof char(6),Depart varchar(10),
primary key (Tno)
)

--向Student表插入数据
insert into Student values (108,'曾华','男','1977-09-01',95033)
insert into Student values (105,'匡明','男','1975-10-02',95031)
insert into Student values (107,'王丽','女','1976-01-23',95033)
insert into Student values (101,'李军','男','1976-02-20',95033)
insert into Student values (109,'王芳','女','1975-02-10',95031)
insert into Student values (103,'陆君','男','1974-06-03',95031)

--向Teacher表插入数据（因为Tno在别的表中被引用为外键，所以必须先创建Teacher表）
insert into Teacher values
(804,'李诚','男','1958-12-02','副教授','计算机系'),
(856,'张旭','男','1969-03-12','讲师','电子工程系'),
(825,'王萍','女','1972-05-05','助教','计算机系'),
(831,'刘冰','女','1977-08-14','助教','电子工程系')

--向Course表插入数据
insert into Course (Cno,Cname,Tno) values
('3-105','计算机导论',825),
('3-245','操作系统',804),
('6-166','数字电路',856),
('9-888','高等数学',831)

--向Score表中插入数据
insert into Score (Sno,Cno,Degree) values
(103,'3-245',86),
(105,'3-245',75),
(109,'3-245',68),
(103,'3-105',92),
(105,'3-105',88),
(109,'3-105',76),
(101,'3-105',64),
(107,'3-105',91),
(108,'3-105',78),
(101,'6-166',85),
(107,'6-166',79),
(108,'6-166',81)

--insert into Score (Sno,Cno,Degree) values(109,60116,85)
--alter table Course alter column Cno varchar(5)

--1、查询Student表中的所有记录的Sname、Ssex和Class列
select Sname,Ssex,Class from Student

--2、查询教师所有的单位即不重复的Depart列。
select distinct (Depart) from Teacher

--3、查询Student表的所有记录。
select * from Student

--4、查询Score表中成绩在到之间的所有记录。
select * from Score where Degree between 60 and 80

--5、查询Score表中成绩为85,86或88的记录。
select * from Score where Degree in (85,86,88)

select * from Score where Degree=85 or Degree=86 or Degree=88

--6、查询Student表中“95031”班或性别为“女”的同学记录。
select * from Student where Class = '95031' or Ssex = '女'

select * from Student where Class = '95031' union select * from Student where Ssex = '女'

--7、以Class降序查询Student表的所有记录。
select * from Student order by Class DESC

--8、以Cno升序、Degree降序查询Score表的所有记录。
select * from Score order by Cno ASC,Degree DESC

--9、查询“95031”班的学生人数。
select count(Class) as 学生人数 from Student where Class = '95031'

--10、查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
select Sno,Cno from Score where Degree = (select max(Degree) from Score)

select top 1 Sno,Cno from Score order by Degree DESC

--11、查询‘3-105’号课程的平均分。
select AVG(Degree) as 平均分 from Score where Cno = '3-105'

--12、查询Score表中至少有名学生选修的并以开头的课程的平均分数。(重点! group by 和 where 连用的顺序)
select AVG(Degree) as 平均分 from Score where Cno like '3%' group by Cno having COUNT(Cno)>=5

--13、查询最低分大于70，最高分小于90的Sno列。（group by 的使用）
select Sno from Score group by Sno having MIN(Degree)>70 and MAX(Degree)<90

--14、查询所有学生的Sname、Cno和Degree列。
select Sname,Cno,Degree from Student,Score where Student.Sno = Score.Sno

--15、查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,Degree from Course,Score where Course.Cno = Score.Cno

--16、查询所有学生的Sname、Cname和Degree列。
select Sname,Cname,Degree from Student,Course,Score where Student.Sno = Score.Sno and Course.Cno = Score.Cno

--17、查询“95033”班所选课程的平均分。
select AVG(Degree) as 平均分 from Score where Sno in (select Sno from Student where Class = '95033')

select AVG(Degree) as 平均分 from Score,Student where Student.Sno=Score.Sno and Class = '95033'

--18、假设使用如下命令建立了一个grade表：
create table grade(low int,upp int,rank char(1))
insert into grade values(90,100,'A')
insert into grade values(80,89,'B')
insert into grade values(70,79,'C')
insert into grade values(60,69,'D')
insert into grade values(0,59,'E')

--现查询所有同学的Sno、Cno和rank列。(重点！)
select Sno,Cno,rank from Score,grade where Score.Degree between grade.low and grade.upp

--19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。(重点！，注意，学号为109的同学不是只有一科成绩，或许有多科，所以上 max(Degree))
select * from Score where Cno = '3-105' and Degree > (select MAX(Degree) from Score where Sno = 109)

--20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。(重点！)
select Sno from Score where Degree <> (select MAX(Degree) from Score) group by Sno having COUNT(Sno)>1

--21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。(与19题比较,弄清题意，查询出来的课程号必须为3-105)
select * from Score where Cno='3-105'and Degree >all( select Degree from Score where Sno='109')

--22、查询和学号为的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
select Sno,Sname,Sbirthday from Student where Sbirthday = (select Sbirthday from Student where Sno = 108)

--23、查询“张旭“教师任课的学生成绩。(当Sno,Cno出现在多个表中，必须说明查询的是哪个表的字段)
select Score.Sno,Score.Cno,Degree from Score,Teacher,Course where Course.Tno = Teacher.Tno and Course.Cno = Score.Cno and Teacher.Tname = '张旭'

--24、查询选修某课程的同学人数多于5人的教师姓名。
--（重点！同时含有where和group by语句的，group by 必须放在最后，并且group by 跟的字段需和查询的相一致）
select Tname from Teacher,Score,Course where Score.Cno = Course.Cno and Teacher.Tno = Course.Tno group by Tname having COUNT(Score.Cno)>5

select Tname from Teacher where Tno in(select Course.Tno from Course,Score where Course.Cno= Score.Cno group by Course.Tno having COUNT(Score.Cno)>5)

--25、查询95033班和95031班全体学生的记录。
select * from Student where Class = '95033' or Class = '95031'

select * from Student where Class in ('95033','95031')

--26、查询存在有85分以上成绩的课程Cno。（容易混淆）
select Cno from Score group by Cno having max(Degree)>=85

select Cno from Score where Degree >85 (此查询语句不正确)

--27、查询出“计算机系“教师所教课程的成绩表。
select * from Score,Teacher,Course where Teacher.Tno = Course.Tno and Course.Cno = Score.Cno and Teacher.Depart = '计算机系'

select * from Score where cno in(select cno from Course where tno in(select tno from teacher where depart='计算机系'))

--29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select Cno,Sno,Degree from Score where Cno = '3-105' and Degree > any(select Degree from Score where Cno = '3-245') order by Degree DESC

select Cno,Sno,Degree from Score where Cno = '3-105' and Degree > (select MIN(Degree) from Score where Cno = '3-245') order by Degree

--30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree. (与29题比较)
select Cno,Sno,Degree from Score where Cno = '3-105' and Degree > all(select Degree from Score where Cno = '3-245')

select Cno,Sno,Degree from Score where Cno = '3-105' and Degree > (select MAX(Degree) from Score where Cno = '3-245')

--31、查询所有教师和同学的name、sex和birthday.（union的使用，集合查询）
select sname [name],ssex sex,sbirthday birthday from student union select tname name,tsex sex,tbirthday birthday from teacher

--32、查询所有“女”教师和“女”同学的name、sex和birthday.(重点！连接查询，和31题比较)
select sname [name],ssex sex,sbirthday birthday from student where ssex='女' union select tname name,tsex sex,tbirthday birthday from teacher where tsex='女'

--34、查询所有任课教师的Tname和Depart. (此处有任课老师，所以是Course表)
select Teacher.Tname,Depart from Teacher,Course where Teacher.Tno = Course.Tno
select Tname,Depart from Teacher where Tno in (select Tno from Course)

--35、查询所有未讲课的教师的Tname和Depart.
select Tname,Depart from Teacher where Tno not in (select Tno from Course)

--36、查询至少有名男生的班号。(重点!)
--select Class from Student group by Class having COUNT(Ssex)>=2 and Ssex = '男' (错误)
--HAVING 子句中的列'Student.Ssex' 无效，因为该列没有包含在聚合函数或GROUP BY 子句中。
select Class from Student where Ssex = '男' group by Class having COUNT(Ssex)>=2

--37、查询Student表中不姓“王”的同学记录。
select * from Student where Sname not like '王%'

--38、查询Student表中每个学生的姓名和年龄。(重点！内置函数的使用)
select Sname,(YEAR(getdate())-YEAR(Sbirthday)) as age from Student

--39、查询Student表中最大和最小的Sbirthday日期值。
select MAX(Sbirthday) as max ,MIN(Sbirthday) as min from Student

select sbirthday from student where sbirthday in(select min(sbirthday)from student) union
select sbirthday from student where sbirthday in(select max(sbirthday)from student)
--40、以班号和年龄从大到小的顺序查询Student表中的全部记录。(班号和年龄不能只用一个DESC,必须分开使用)
select * from Student order by Class DESC,(YEAR(getdate())-YEAR(Sbirthday)) DESC

--41、查询“男”教师及其所上的课程。
select Course.Cname,Cno,Course.Tno from Teacher,Course where Teacher.Tno = Course.Tno and Tsex = '男'

select cname from course where cno in(select cno from course where tno in(select tno from teacher where tsex='男'))

--42、查询最高分同学的Sno、Cno和Degree列。
--select Score.Sno,Cno,Degree from Score group by Degree having Degree = MAX(Degree)
select Score.Sno,Cno,Degree from Score where Degree in (select MAX(Degree) from Score)

--43、查询和“李军”同性别的所有同学的Sname.
select Sname from Student where Ssex = (select Ssex from Student where Sname = '李军')

--44、查询和“李军”同性别并同班的同学Sname.
select Sname from Student where Ssex = (select Ssex from Student where Sname = '李军')
and Class =(select Class from Student where Sname = '李军') and sname not in('李军')

--45、查询所有选修“计算机导论”课程的“男”同学的成绩表。
select * from Score where Cno in (select Cno from Course where Cname = '计算机导论') and Sno in (select Sno from Student where Ssex = '男')

--46、找出每个学生超过他选修课程平均成绩的课程号 (自连接，子查询)
select Sno,Cno,Degree from Score as a where Degree >= (select AVG(Degree) from Score as b where a.Sno = b.Sno)