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作业批注和复习,MySQL查询语句实际操作演习

作者: MySQL数据库  发布:2019-12-11

三.完成以下操作

0.根据上述题目和表格,创建相应数据库,创建相应表结构,并插入给定数据

create database ClassManager;
use ClassManager1;

create table student (
sno varchar(20) not null comment '学号',
sname varchar(20) not null comment '学生姓名',
ssex varchar(20) not null comment '学生性别',
sbirthday datetime comment '学生出生年月',
class varchar(20) comment '学生所在班级'
);

create table course (
cno varchar(20) not null comment '课程号',
cname varchar(20) not null comment '课程名称',
tno varchar(20) not null comment '教工编号'
);

create table score (
sno varchar(20) not null comment '学号',
cno varchar(20) not null comment '课程号',
degree decimal(4,1) comment '成绩'
);

create table teacher (
tno varchar(20) not null comment '教工编号',
tname varchar(20) not null comment '教工姓名',
tsex varchar(20) not null comment '教工性别',
tbirthday datetime comment '教工出生年月',
prof varchar(20) comment '职称',
depart varchar(20) not null comment '教工所在部门'
);

insert into student (sno, sname, ssex, sbirthday, class) values ('108',    '曾华','男','1977-09-01','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('105',    '匡明','男','1975-10-02','95031');
insert into student (sno, sname, ssex, sbirthday, class) values ('107',    '王丽','女','1976-01-23','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('101',    '李军','男','1976-02-20','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('109',    '王芳','女','1975-02-10','95031');
insert into student (sno, sname, ssex, sbirthday, class) values ('103',    '陆君','男','1974-06-03','95031');

insert into course (cno, cname, tno) values ('3-105', '计算机导论',  '825');
insert into course (cno, cname, tno) values ('3-245', '操作系统',    '804');
insert into course (cno, cname, tno) values ('6-166', '数字电路',    '856');
insert into course (cno, cname, tno) values ('9-888', '高等数学',    '831');

insert into score (sno, cno, degree) values ('103', '3-245', '86');
insert into score (sno, cno, degree) values ('105', '3-245', '75');
insert into score (sno, cno, degree) values ('109', '3-245', '68');
insert into score (sno, cno, degree) values ('103', '3-105', '92');
insert into score (sno, cno, degree) values ('105', '3-105', '88');
insert into score (sno, cno, degree) values ('109', '3-105', '76');
insert into score (sno, cno, degree) values ('101', '3-105', '64');
insert into score (sno, cno, degree) values ('107', '3-105', '91');
insert into score (sno, cno, degree) values ('108', '3-105', '78');
insert into score (sno, cno, degree) values ('101', '6-166', '85');
insert into score (sno, cno, degree) values ('107', '6-166', '79');
insert into score (sno, cno, degree) values ('108', '6-166', '81');


insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('804', '李诚','男','1958-12-02','副教授','计算机系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('856', '张旭','男','1969-03-12','讲师','电子工程系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('825', '王萍','女','1972-05-05','助教','计算机系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('831', '刘冰','女','1977-08-14','助教','电子工程系');
  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60到80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);

  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';

  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(*) from student where class = '95031';

10.查询Score表中的最高分的学生学号和课程号。

select * from score sc  where degree = (select max(degree) as max from score where cno = sc.cno group by cno);

11.查询每门课的平均成绩。

select cno, avg(degree) as avg from score group by cno;

12.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 cno, avg(degree) as avg from score where cno like '3%' group by cno having count(*) >= 5;

13.查询分数大于70,小于90的Sno列。

select sno from score where degree > 70 and degree < 90;

14.查询所有学生的Sname、Cno和Degree列。

select sname, cno, degree from student s left join score sc on sc.sno = s.sno;

15.查询所有学生的Sno、Cname和Degree列。

select s.sno, c.cname, sc.degree from student s left join score sc on sc.sno = s.sno left join course c on c.cno = sc.cno;

16.查询所有学生的Sname、Cname和Degree列。

select s.sname, c.cname, sc.degree from student s left join score sc on sc.sno = s.sno left join course c on c.cno = sc.cno;

17.查询“95033”班学生的平均分。

select cno , avg(degree)  from score sc where sc.sno in (select sno from student where class = '95033') group by cno;

18.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 score where sno = '109' and cno = '3-105';

19.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 score where  cno = '3-105' and degree > (select degree from score where sno = '109'and cno = '3-105'); -- 此处理解为只看‘3-105’课程成绩
select * from score where degree > (select degree from score where sno = '109'and cno = '3-105'); -- 此处为各科成绩都算。

20.查询和学号为108、101的同学同年出生的所有学生的Sno、Sname和Sbirthday列。(使用year()方法对生日字段求年份)

select sno,sname,sbirthday from student where year(sbirthday) in (select year(sbirthday) from student where sno in ('108', '101'));

21.查询“张旭“教师任课的学生成绩。

select sc.* from score sc inner join course c on c.cno = sc.cno inner join teacher t on t.tno = c.tno where t.tname = '张旭'; -- 合并多个表然后查询
select * from score where cno in(select cno from course where tno in(select tno from teacher where tname ='张旭')); -- 嵌套查询

22.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 = (select tno from course where cno = (select cno from score group by cno having count(*) > 5));

23.查询95033班和95031班全体学生的记录。

select * from student where class in ('95033', '95031');

24.查询存在有85分以上成绩的课程Cno。

select distinct cno from score where degree > 85;

25.查询出“计算机系“教师所教课程的成绩表。

select * from score where cno in (select cno from course where tno in (select tno from teacher where depart = '计算机系')); 

26.查询“计算 机系”与“电子工程系“不同职称的教师的Tname和Prof。

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');

27.查询所有教师和同学的name、sex和birthday。

select sname as `name`, ssex as `sex`, sbirthday as `birthday` from student union select tname, tsex,tbirthday from teacher;

28.查询所有“女”教师和“女”同学的name、sex和birthday。

select sname as `name` , ssex as `sex`, sbirthday as `birthday`from student where ssex = '女' union select tname, tsex , tbirthday from teacher where tsex = '女';

29.查询成绩比该课程平均成绩低的同学的成绩表。

select * from score sc where degree < (select avg(degree) as avg from score where cno = sc.cno group by cno);

30.查询所有任课教师的Tname和Depart。

select tname, depart from teacher where tno in (select tno from course);

31.查询所有未讲课的教师的Tname和Depart。

select tname, depart from teacher where tno in (select tno from course where cno not in (select cno from score)); -- 此处理解为没有成绩的课程为未讲课的课程。

32.查询至少有2名男生的班号。

select class from student where ssex = '男' group by class having count(*) >= 2;

33.查询Student表中不姓“王”的同学记录。

select * from student where sname not like '王%';

34.查询Student表中每个学生的姓名和年龄(使用year()方法对日期字段)。

select sname, (year(now()) - year(sbirthday)) as nian_ling from student;

35.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;

36.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; 

37.查询“男”教师及其所上的课程。

select t.*, c.cno, c.cname from teacher t inner join course c on c.tno = t.tno where t.tsex = '男';

38.查询最高分同学的Sno、Cno和Degree列。

select sno, cno, degree from score sc where degree = (select max(degree) as max from score where cno = sc.cno group by cno);

39.查询和“李军”同性别的所有同学的Sname。

select sname from student where ssex in (select ssex from student where sname = '李军');

40.查询和“李军”同性别并同班的同学Sname。

select sname from student where ssex in (select ssex from student where sname = '李军') and class in (select class from student where sname = '李军');

41.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');

 

--第三十九题 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

#Course课程表

二.表1-2数据库中的数据

表(一)Student

Sno

Sname

Ssex

Sbirthday

class

108

曾华

1977-09-01

95033

105

匡明

1975-10-02

95031

107

王丽

1976-01-23

95033

101

李军

1976-02-20

95033

109

王芳

1975-02-10

95031

103

陆君

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

1958-12-02

副教授

计算机系

856

张旭

1969-03-12

讲师

电子工程系

825

王萍

1972-05-05

助教

计算机系

831

刘冰

1977-08-14

助教

电子工程系

--第三十一题 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

select * from Score where Degree between 60 and 80

一.表1-1数据库的表结构

表(一)Student (学生表) 

属性名

数据类型

可否为空

含 义

Sno

varchar (20)

学号

Sname

varchar (20)

学生姓名

Ssex

varchar (20)

学生性别

Sbirthday

datetime

学生出生年月

Class

varchar (20)

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)

课程号

Cname

varchar (20)

课程名称

Tno

varchar (20)

教工编号

表(三)Score(成绩表)

属性名

数据类型

可否为空

含 义

Sno

varchar (20)

学号

Cno

varchar (20)

课程号

Degree

Decimal(4,1)

成绩

表(四)Teacher(教师表)

属性名

数据类型

可否为空

含 义

Tno

varchar (20)

教工编号

Tname

varchar (20)

教工姓名

Tsex

varchar (20)

教工性别

Tbirthday

datetime

教工出生年月

Prof

varchar (20)

职称

Depart

varchar (20)

教工所在部门

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

 

题目:新建一个数据库ClassManager,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。

--第二十九题 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 Teacher,Course,Score where Teacher.Depart='计算机系'and Teacher.Tno=Course.Tno and Course.Cno=Score.Cno

--第十七题 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')

insert into Score values('','108','3-105','78');

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

insert into Student values('101','李军','男','1976-02-20','95033');

1、连接查询
列的扩展 join on

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

--第十三题 查询分数大于70,小于90的Sno列。
select sno from Score where Degree between 70 and 90

35 、 查询所有未讲课的教师的Tname和Depart.

select * from Score where Cno='3-105' and Degree >any(select Degree from Score where Cno='3-245')

 

--第二十三题 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 * from Student order by Class desc

select top 1* from Score order by Degree desc

 

--第二十一题 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')

24、查询选修某课程的同学人数多于5人的教师姓名。

--第三十五题 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)
--第三十六题 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

14、查询所有学生的Sname、Cno和Degree列。

5、模糊查询 like
select * from 表名 where 列名 like '%_'

23、查询“张旭“教师任课的学生成绩。

9、去重查询

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。

10、聚合函数(统计函数)
select count(*) from 表名

22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。

--第二十四题 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) )

select * from Student order by Sbirthday,Class desc

--第八题 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

#创建表

--第四十一题 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

45、查询所有选修“计算机导论”课程的“男”同学的成绩表。

--第十六题 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

 

--第九题 查询“95031”班的学生人数。
select count(*) from student where Class='95031' --*可以换成主键值

 

--第十八题 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 * from score where cno in(select cno from course where tno in(select tno from teacher where depart='计算机系'))

2、子查询
(1)无关子查询
子查询和父查询没有一定的关系,子查询可以单独执行

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。

--第十二题 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

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

--第二十八题 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 a where Prof not in(select Prof from Teacher b where a.Depart!=b.Depart)

 

--第二十五题 查询95033班和95031班全体学生的记录。
select * from student where Class='95033' or Class='95031'

Select Cno from score where degree>85

删除

 

(2)相关子查询
子查询执行的时候必须使用父查询的内容作为条件

select Cno,Tname from Course,Teacher where course.tno=teacher.tno and Tsex='男'

 

13、查询分数大于70,小于90的Sno列。

修改

 

--第三十四题 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)

28、查询“计算 机系”与“电子工程系“不同职称的教师的Tname和Prof。

delete from 表名 where 筛选条件

select avg(degree) from score where sno in(select sno from student where class='95033' )

select * from 表名 where 列名 in (数据列表)

39、查询Student表中最大和最小的Sbirthday日期值。

select 列名 as 别名 from 表名

select * from Score order by Cno,Degree desc

AVG max min

6、 查询Student表中“95031”班或性别为“女”的同学记录。

--第三十七题 查询Student表中不姓“王”的同学记录。
select * from student where Sname not like ('王%')

insert into Student values('108','曾华','男','1977-09-01','95033');

--第四十四题 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')

 

--第三十题 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)

 

增加 
insert into 表名 values (每一列的值)

Select * from Student where class in ('95033','95031')

7、分组查询

insert into Score values('','105','3-105','88');

2、表操作
create table 表名(列名 类型 其他,列名 类型,其他)
primary key 主键
identity 自增长列
not null 非空
unique 唯一
references 外键 references 主表名(主表主键列)
外键一般是从表的列关联到主表的主键上
drop table 表名 删除表

select sum(Class=95031) from Student

--第二十二题 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')

Select Sname,Ssex,Sbirthday from Student
union
Select Tname,Tsex,Tbirthday from Teacher

复习

37、查询Student表中不姓“王”的同学记录。

--第二十七题 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'))

insert into Score values('','101','6-166','85');

--第五题 查询Score表中成绩为85,86或88的记录。
select * from Score where Degree in ('85','86','88')

 

update 表名 set 列名=值,列名=值 where 筛选条件

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.

 

insert into Course values('3-245','操作系统','804');

--第三题 查询Student表的所有记录。
select * from student

#添加数据

1、数据库操作
create database 数据库名称
drop database 数据库名称
use 数据库名称
go 两条SQL语句之间的间隔

select Sname,year(now())-year(Sbirthday) from Student

--第十五题 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

 

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

31、 查询所有教师和同学的name、sex和birthday.

--第四十二题 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 * from score where sno in(select sno from score group by sno having count(*)>1) and degree<(select max(degree) from score where sno in
(select sno from score group by sno having count(*)>1))

2、
条件查询

select Tname,Depart from Teacher where Tno in(select Tno from Course where Cno not in(select Cno from Score group by Cno))

--第二十题 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)

 

select * from 表名 group by 列名 having 条件

36、查询至少有2名男生的班号。

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

select sno,cno,rank from score,grade where degree between low and upp

--第二十六题 查询存在有85分以上成绩的课程Cno.
select distinct cno from Score where Degree>85

26、 查询存在有85分以上成绩的课程Cno.

insert into 表名 (列名) values (列的值)

select avg(degree) from Score group by Cno having count(*)>=5 and Cno like'3%'

--第四题 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

insert into Teacher values('804','李诚','男','1958-12-02','副教授','计算机系');

select 列名 from 表名

insert into Student values('109','王芳','女','1975-02-10','95031');

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

8、 以Cno升序、Degree降序查询Score表的所有记录。

3、范围查询 between and

insert into Score values('','103','3-245','86');

select * from 表名 where 条件1

17、 查询“95033”班学生的平均分。

--第四十题 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

insert into Score values('','107','3-105','91');

select distinct 列名 from 表米

 

--第四十五题 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')

43、查询和“李军”同性别的所有同学的Sname.

--第六题 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 Score where Cno='3-105' and Degree>(select max(Degree) from Score where Sno='109'and Cno='3-105')

--第十题 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 Sno,Sname,Sbirthday from Student where year(Sbirthday)=(select year(Sbirthday) from Student where Sno='108')

二、高级查询

 

select sun(列名) from 表名

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。

 

Select Degree from score a where Degree<(Select Avg(Degree) from score b where cno=a.cno)

8、分页查询 top n 去前n个值
select top n 表名

insert into Student values('103','陆君','男','1974-06-03','95031');

--第十一题 查询每门课的平均成绩。
select Cno,AVG(Degree) as 平均分 from Score group by Cno

 

查询
1、简单查询
select * from 表名

select * from Student where Sname not like '王%'

select * from 表名 where 条件1 and 条件2

create table Teacher #教师表
(
Tno varchar(20) not null primary key,
Tname varchar(20) not null,
Tsex varchar(20) not null,
Tbirthday datetime,
Prof varchar(20),
Depart varchar(20) not null
);

--第二题 查询教师所有的单位即不重复的Depart列。
select distinct Depart from Teacher

 

6、排序查询 desc 降序

Select Sno,Cno,Degree from Score where Degree=(select max(Degree) from Score)

--第三十八题 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

select * from 表名 order by 列名

 

3、数据操作

33、 查询成绩比该课程平均成绩低的同学的成绩表。

--第四十三题 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')

create table Score #成绩表
(
ids int auto_increment primary key,
Sno varchar(20) not null,
foreign key (Sno) references Student(Sno),
Cno varchar(20) not null,
foreign key (Cno) references Course(Cno),
Degree Decimal(4,1)
);

--第七题 以Class降序查询Student表的所有记录。
select * from student order by Class desc

insert into Teacher values('856','张旭','男','1969-03-12','讲师','电子工程系');

4、离散查询

insert into Teacher values('825','王萍','女','1972-05-05','助教','计算机系');

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

7、 以Class降序查询Student表的所有记录。

--第十四题 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

select sname,cno,degree from student,score where student.sno = score.sno

--第三十三题 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)

select Sno from Score where degree>70 and degree<90

--第三十二题 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'

select Sname from Student where Ssex=(select Ssex from Student where Sname='李军')

联合查询 行的扩展 union

40、以班号和年龄从大到小的顺序查询Student表中的全部记录。

--第一题 查询Student表中的所有记录的Sname、Ssex和Class列。
select Sname,Ssex,Class from student

9、 查询“95031”班的学生人数。

--第十九题 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')

select * from Score where Cno='3-105' and Degree>(select max(Degree) from Score where Sno='109')

select * from 表名 where 条件1 or 条件2

42、查询最高分同学的Sno、Cno和Degree列。

select * from 表名 where 列名 between 值 and 值2

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)

 

insert into Score values('','101','3-105','64');

 

25、查询95033班和95031班全体学生的记录。

insert into Score values('','108','6-166','81');

Select degree from score where Cno in(Select Cno from course where Tno=(Select Tno from Teacher where Tname='张旭'))

44、查询和“李军”同性别并同班的同学Sname.

insert into Score values('','107','6-166','79');

18、 假设使用如下命令建立了一个grade表:
create table grade(low int(3),upp int(3),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 distinct Depart from Teacher

#Student学生表

select class from Student where Ssex='男' group by Class having count(*)>=2

select sno,cname,degree from course,score where course.cno = score.cno

 

 

 

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')

insert into Student values('107','王丽','女','1976-01-23','95033');

1、 查询Student表中的所有记录的Sname、Ssex和Class列。

 

 

 

38、查询Student表中每个学生的姓名和年龄。

Select Sname,Ssex,Sbirthday from Student where Ssex='女'
union
Select Tname,Tsex,Tbirthday from Teacher where Tsex='女'

2、 查询教师所有的单位即不重复的Depart列。

insert into Score values('','109','3-245','68');

 

select Tname,Depart from Teacher where Tno in(select Tno from Course where Cno in(select Cno from Score group by Cno))

 

15、查询所有学生的Sno、Cname和Degree列。

select Sname from Student where Ssex=(select Ssex from Student where Sname='李军') and class=(select Class from Student where Sname='李军')

insert into Score values('','109','3-105','76');

34、 查询所有任课教师的Tname和Depart.

41、查询“男”教师及其所上的课程。

 

select Sno,Cno from Score where degree=(select max(degree) from Score)

 

11、 查询每门课的平均成绩。

select * from Student

 

#Score成绩表

27、查询出“计算机系“教师所教课程的成绩表。

 

#Teacher教师表

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。

insert into Score values('','105','3-245','75');

select sname,cname,degree from student,course,score where student.sno=score.sno and course.cno = score.cno

4、 查询Score表中成绩在60到80之间的所有记录。

 

5、 查询Score表中成绩为85,86或88的记录。

 

create table Student #学生表
(
Sno varchar(20) not null primary key,
Sname varchar(20) not null,
Ssex varchar(20) not null,
Sbirthday datetime,
Class varchar(20)
);

 

12、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。

3、 查询Student表的所有记录。

select degree from score where Cno=(select Cno from Course where Cname='计算机导论') and Sno in (select sno from Student where Ssex='男')

select * from Score where Degree in(85,86,88)

insert into Course values('3-105','计算机导论','825');

select Sname,Ssex,Class from Student

select min(Sbirthday),min(Sbirthday) from Student

insert into Score values('','103','3-105','92');

Select Tname from teacher where Tno=( Select Tno from course where Cno=( Select Cno from score group by Cno having count(*)>5))

create table Course #课程表
(
Cno varchar(20) not null primary key,
Cname varchar(20) not null,
Tno varchar(20) not null,
foreign key (Tno) references Teacher(Tno)
);

insert into Student values('105','匡明','男','1975-10-02','95031');

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

insert into Course values('6-166','数字电路','856');

 

insert into Course values('9-888','高等数学','831');

select avg(degree),Cno from score group by Cno;

 

 

32、查询所有“女”教师和“女”同学的name、sex和birthday.

insert into Teacher values('831','刘冰','女','1977-08-14','助教','电子工程系');

16、查询所有学生的Sname、Cname和Degree列。

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