sql查询，学生表例子(自用)

Posted 2021-02-04 wjwap

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 (学生use)                         
属性名    数据类型    可否为空    含 义
Sno    varchar (20)    否    学号（主码）
Sname    varchar (20)    否    学生姓名
Ssex    varchar (20)    否    学生性别
Sbirthday    Datetime    可    学生出生年月
 Class    varchar (20)    可    学生所在班级

表（二）Course（课程表）
属性名    数据类型    可否为空    含 义
Cno    varchar (20)    否    课程号（主码）
Cname    varchar (20)    否    课程名称
Tno    varchar (20)    否    教工编号
表（三）Score(成绩表)
属性名    数据类型    可否为空    含 义
Id    Int        主键 自增
Sno    varchar (20)    否    学号
Cno    varchar (20)    否    课程号
Degree    Decimal(4,1)
    可    成绩
//主码：Sno+ Cno
表（四）Teacher(教师表)
属性名    数据类型    可否为空    含 义
Tno    varchar (20)    否    教工编号（主码）
Tname    varchar (20)    否    教工姓名
Tsex    varchar (20)    否    教工性别
Tbirthday    datetime    可    教工出生年月
Prof    varchar (20)    可    职称
Depart    varchar (20)    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
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 * from score where degree > 68 and cno = ‘3-105’ order by degree desc;

Select min(degree) from score where cno = ‘3-245’;


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

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

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

 查询Student表的所有记录。
select * from student

查询Score表中成绩在60到80之间的所有记录。
select * from Score where Degree between 60 and 80

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

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‘

以Class降序查询Student表的所有记录。
select * from student order by Class desc

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

查询“95031”班的学生人数。
select count(*) from student where Class=‘95031‘ --*可以换成主键值

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)

查询每门课的平均成绩。
select Cno,AVG(Degree) as 平均分 from Score group by Cno

select Cname from Course where Cno in (select Cno a from Score group by Cno)
union
select Cno,AVG(Degree) from Score group by Cno

查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select AVG(Degree ) from Score where Cno like ‘3%‘ group by Cno having COUNT(Cno)>4

查询分数大于70，小于90的Sno列。
select sno from Score where Degree between 70 and 90

查询所有学生的Sname、Cno和Degree列。
select Sname,Cno,Degree from student join Score on student.Sno=Score.Sno

查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,degree from Score join Course on Course.Cno=Score.Cno

查询所有学生的Sname、Cname和Degree列。
select student.Sname,Cname,degree from student join Score on student.Sno=Score.Sno join Course on Course.Cno=Score.Cno

查询“95033”班学生的平均分。
select AVG(Degree) from Score where Sno in (select Sno from student where Class=‘95033‘)

select AVG(Degree) from Score,student where student.Sno=Score.Sno and Class=‘95033‘

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。

select Sno,Cno,Degree,[RANK] from grade join Score on Score.Degree between low and upp

select Sno,Cno,Degree,[RANK] from Score,grade where Degree between low and upp

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。
select * from student,Score where Score.Cno=‘3-105‘ and student.Sno=Score.Sno and Score.Degree>(select Degree from Score where Cno=‘3-105‘ and Sno=‘109‘)

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。
select * from Score a where Degree <(select MAX(degree) from Score b where a.Cno=b.Cno) and Sno in(select Sno from Score group by Sno having count(*)>1)

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 student,Score where student.Sno=Score.Sno and Score.Degree>(select Degree from Score where Cno=‘3-105‘ and Sno=‘109‘)

查询和学号为107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 year(student.Sbirthday)=(select year(Sbirthday) from student where Sno=‘107‘)

查询“张旭“教师任课的学生成绩。
--select Degree from Score,Teacher,Course where Teacher.Tname=‘张旭‘ and Teacher.Tno=Course.Tno and Course.Cno=Score.Cno

select Sno,Cno,Degree from Score where Cno in (select Cno from Course where Tno in (select Tno from Teacher where Tname=‘张旭‘))

查询选修某课程的同学人数多于5人的教师姓名。
select Tname from Teacher where Tno in (select Tno from Course where Cno in (select Cno from Score group by Cno having COUNT(*)>5) )

查询95033班和95031班全体学生的记录。
select * from student where Class=‘95033‘ or Class=‘95031‘

查询存在有85分以上成绩的课程Cno.
select distinct cno from Score where Degree>85

查询出“计算机系“教师所教课程的成绩表。
select sno,Cno ,Degree from Score where Cno in (select Cno from Course where Tno in (select tno from Teacher where Depart=‘计算机系‘))

 查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。使用相关子查询

　　select tname,prof from teacher where depart=‘计算机系‘ and prof not in (select prof from teacher where depart=‘电子工程系‘);
　　union
　　select tname,prof from teacher where depart=‘电子工程系‘ and prof not in (select prof from teacher where depart=‘计算机系‘);

select Tname,Prof from Teacher a where Prof not in(select Prof from Teacher b where a.Depart!=b.Depart)

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”课程的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select Cno,Sno,Degree from Score a where (select Degree from Score b where Cno=‘3-105‘ and b.Sno=a.Sno)>=(select Degree from Score c where Cno=‘3-245‘ and c.Sno=a.Sno) order by Degree desc


select * from Score where Cno=‘3-105‘ and Degree >any(select Degree from Score where Cno=‘3-245‘)
查询选修编号为“3-105”课程且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
select Cno,Sno,Degree from Score a where (select Degree from Score b where Cno=‘3-105‘ and b.Sno=a.Sno)>(select Degree from Score c where Cno=‘3-245‘ and c.Sno=a.Sno)

select cno,sno,degree from score where cno=‘3-105‘ and degree>all(select degree from score where cno=‘3-245‘) order by degree desc
查询所有教师和同学的name、sex和birthday.
select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher

查询所有“女”教师和“女”同学的name、sex和birthday.
select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student where Ssex=‘女‘
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher where Tsex=‘女‘

查询成绩比该课程平均成绩低的同学的成绩表。
select Sno,Cno,Degree from Score a where a.Degree<(select AVG(Degree) from Score b where a.Cno=b.Cno)

查询所有任课教师的Tname和Depart.
select Tname,Depart from Teacher where Tname in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)

select Tname,Depart from Teacher where tno in (select tno from course where Cno in (select distinct Cno from Score))

查询所有未讲课的教师的Tname和Depart.
select Tname,Depart from Teacher where Tname not in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)
查询至少有2名男生的班号。
select Class FROM    student where Ssex=‘男‘ group by Class having COUNT(*)>1


查询Student表中不姓“王”的同学记录。
select * from student where Sname not like (‘王%‘)

查询Student表中每个学生的姓名和年龄。
select Sname,YEAR(GETDATE())-year(Sbirthday) from student

查询Student表中最大和最小的Sbirthday日期值。
select MAX(Sbirthday) as 最大,MIN(Sbirthday) as 最小 from student

以班号和年龄从大到小的顺序查询Student表中的全部记录。
select * from student order by Class desc,Sbirthday asc

查询“男”教师及其所上的课程。
select Tname,Cname from Teacher,Course where Tsex=‘男‘ and Teacher.Tno=Course.Tno


查询最高分同学的Sno、Cno和Degree列。
select Sno,Cno,Degree from Score where degree=(select MAX(Degree)from Score)

select top 1* from Score order by Degree desc

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‘) and Sname not in (‘李军‘)

 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 Sname not in (‘李军‘) and Class=(select Class from student where Sname=‘李军‘)

查询所有选修“计算机导论”课程的“男”同学的成绩表。
select Sno,Degree from Score where Sno in (select Sno from student where Ssex=‘男‘) and Cno in (select Cno from Course where Cname=‘计算机导论‘