MySQL查詢語句的45道練習


 
 
 
 
 

一、設有一數據庫,包括四個表:學生表(Student)、課程表(Course)、成績表(Score)以及教師信息表(Teacher)。四個表的結構分別如表1-1的表(一)~表(四)所示,數據如表1-2的表(一)~表(四)所示。用SQL語句創建四個表並完成相關題目。

                 1-1數據庫的表結構

表(一)Student (學生表) 

屬性名

數據類型

可否為空

含 義

Sno

varchar (20)

學號(主碼)

Sname

varchar (20)

學生姓名

Ssex

varchar (20)

學生性別

Sbirthday

datetime

學生出生年月

Class

varchar (20)

學生所在班級

 

表(二)Course(課程表)

屬性名

數據類型

可否為空

含 義

Cno

varchar (20)

課程號(主碼)

Cname

varchar (20)

課程名稱

Tno

varchar (20)

教工編號(外碼)

表(三)Score(成績表)

屬性名

數據類型

可否為空

含 義

Sno

varchar (20)

學號(外碼)

Cno

varchar (20)

課程號(外碼)

Degree

Decimal(4,1)

成績

主碼:Sno+ Cno

表(四)Teacher(教師表)

屬性名

數據類型

可否為空

含 義

Tno

varchar (20)

教工編號(主碼)

Tname

varchar (20)

教工姓名

Tsex

varchar (20)

教工性別

Tbirthday

datetime

教工出生年月

Prof

varchar (20)

職稱

Depart

varchar (20)

教工所在部門

1-2數據庫中的數據

表(一)Student

Sno

Sname

Ssex

Sbirthday

class

108

曾華

1977-09-01

95033

105

匡明

1975-10-02

95031

107

王麗

1976-01-23

95033

101

李軍

1976-02-20

95033

109

王芳

1975-02-10

95031

103

陸君

1974-06-03

95031

 

表(二)Course

Cno

Cname

Tno

3-105

計算機導論

825

3-245

操作系統

804

6-166

數字電路

856

9-888

高等數學

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

李誠

1958-12-02

副教授

計算機系

856

張旭

1969-03-12

講師

電子工程系

825

王萍

1972-05-05

助教

計算機系

831

劉冰

1977-08-14

助教

電子工程系

 

復制代碼
復制代碼
#建學生信息表student
create table student
(
sno varchar(20) not null primary key,
sname varchar(20) not null,
ssex varchar(20) not null,
sbirthday datetime,
class varchar(20)

);
#建立教師表
create table teacher
(
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

);
#建立課程表course
create table course
(
cno varchar(20) not null primary key,
cname varchar(20) not null,
tno varchar(20) not null,
foreign key(tno) references teacher(tno)

);
#建立成績表
create table score
(
sno varchar(20) not null primary key,
foreign key(sno) references student(sno),
cno varchar(20) not null,
foreign key(cno) references course(cno),
degree decimal

);

#添加學生信息
insert into student values('108','曾華','男','1977-09-01','95033');
insert into student values('105','匡明','男','1975-10-02','95031');
insert into student values('107','王麗','女','1976-01-23','95033');
insert into student values('101','李軍','男','1976-02-20','95033');
insert into student values('109','王芳','女','1975-02-10','95031');
insert into student values('103','陸君','男','1974-06-03','95031');




#添加教師表
insert into teacher values('804','李誠','男','1958-12-02','副教授','計算機系');
insert into teacher values('856','張旭','男','1969-03-12','講師','電子工程系');
insert into teacher values('825','王萍','女','1972-05-05','助教','計算機系');
insert into teacher values('831','劉冰','女','1977-08-14','助教','電子工程系');

#添加課程表
insert into course values('3-105','計算機導論','825');
insert into course values('3-245','操作系統','804');
insert into course values('6-166','數字電路','856');
insert into course values('9-888','高等數學','831');
#添加成績表

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

 

 

 

1、 查詢Student表中的所有記錄的Sname、Ssex和Class列。

1
select Sname,Ssex,Class from student

2、 查詢教師所有的單位即不重復的Depart列。

1
select distinct Depart from teacher

3、 查詢Student表的所有記錄。

1
select from student

4、 查詢Score表中成績在60到80之間的所有記錄。

1
select from Score where Degree between 60 and 80

5、 查詢Score表中成績為85,86或88的記錄。

1
select from Score where Degree in (85,86,88)

6、 查詢Student表中“95031”班或性別為“女”的同學記錄。

1
select from Student where class= '95031' or Ssex= '女'

7、 以Class降序查詢Student表的所有記錄。

1
select from student order by class desc

8、 以Cno升序、Degree降序查詢Score表的所有記錄。

1
select from Score order by cno asc ,degree desc

9、 查詢“95031”班的學生人數。

1
select count (*)  from student where class= '95031'

10、     查詢Score表中的最高分的學生學號和課程號。(子查詢或者排序)

1
select Sno,Cno  from Score where Degree=( select max (Degree) from Score)
1
select Sno,Cno  from Score order by  Degree desc limit 0,1

11、     查詢每門課的平均成績。

1
select Cno, avg (degree) from Score group by Cno

12、     查詢Score表中至少有5名學生選修的並以3開頭的課程的平均分數。

1
select avg (Degree) from score where Cno like '3%' and Cno in ( select Cno from score group by Cno having count (*)>=5) 用 in 不用= 是因為可能會有多個
1
簡單寫法: select avg (Degree) from score where Cno like '3%' and group by Cno having count (*)>=5

13、     查詢分數大於70,小於90的Sno列。

1
select Sno from Score where degree>70 and degree<90

14、     查詢所有學生的Sname、Cno和Degree列。

1
select  Sname, Cno,Degree from Score , student where Score.Sno=student.Sno

15、     查詢所有學生的Sno、Cname和Degree列。

1
select  Sno,Cname,Degree from Score , Course where Score.Cno=Course.Cno

16、     查詢所有學生的Sname、Cname和Degree列。

1
select Sname,Cname,Degree from student,course,score where student.Sno=score.Sno and course.Cno=score.Cno
1
join .. on 寫法: select Sname,Cname,Degree from student join score on student.Sno=score.Sno join course on course.Cno=score.Cno

17、     查詢“95033”班學生的平均分。

1
select avg (degree) as 'class=95033' from Score where Sno in ( select Sno from  Student where Class= '95033' )  

18、 假設使用如下命令建立了一個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’)

現查詢所有同學的Sno、Cno和rank列。

1
select Sno,Cno,rank from Score,grade where degree between low and upp

19、查詢選修“3-105”課程的成績高於“109”號同學成績的所有同學的記錄。

1
<span style= "color: #000000; font-size: 15px" >109同學,選修是3-105課的</span>
1
select * from score where Cno= '3-105' and degree>( select max (degree ) from Score where Sno= '109' and Cno= '3-105' )
1
<span style= "font-size: 15px" >109同學,沒有選修3-105課</span>
1
select * from score where Cno= '3-105' and degree>( select max (degree ) from Score where Sno= '109' )

and degree<( select max(degree ) from Score where sno in (select Sno from score group by Sno having count(*)>1))

1
選了多門課程並且是這個課程下不是最高分的
1
select * from score a where Sno in ( select Sno from score group by Sno having count (*)>1) and degree<( select max (degree ) from Score b where b.cno = a.cno)

21、查詢成績高於學號為“109”、課程號為“3-105”的成績的所有記錄。

1
Select * from score where degree>( select degree from Score where Sno= '109' and Cno= '3-105' )

22、查詢和學號為108、101的同學同年出生的所有學生的Sno、Sname和Sbirthday列。

1
select sno,sname,sbirthday  from student where year (sbirthday) = ( select year (sbirthday) from student where  sno= '108' )
1
select sno,sname,sbirthday  from student where year (sbirthday) = ( select year (sbirthday) from student where  sno= '101' )

23、查詢“張旭“教師任課的學生成績。

1
select Sno,degree from score,Course  where score.Cno=Course.Cno and Course.Tno= ( select Tno from Teacher where Tname= '張旭' )
1
select degree from score where Cno in ( select cno from course where Tno= ( select Tno from Teacher where Tname= '張旭'  ) )

24、查詢選修某課程的同學人數多於5人的教師姓名。

1
select Tname from Teacher,  Course where Teacher.Tno=Course.Tno and Course.Cno =( select Cno from Score group by Cno having count (*)>5)
1
select Tname from Teacher where tno=( select Tno from Course where cno=( select Cno from Score group by Cno having count (*)>5 ))

25、查詢95033班和95031班全體學生的記錄。

1
select * from  student where  class in ( '95033' , '95031' )

26、  查詢存在有85分以上成績的課程Cno.

1
select Cno from score where degree>85

27、查詢出“計算機系“教師所教課程的成績表。

1
select * from course  where cno in ( select cno from course  where tno in ( select tno from teacher where Depart= '計算機系' ))

28、查詢“計算 機系”與“電子工程系“不同職稱的教師的Tname和Prof。

1
select Tname,Prof from Teacher where Depart = '計算機系' and Prof  not in ( select Prof from Teacher where Depart = '電子工程系' )<br> union <br> select Tname,Prof from Teacher where Depart = '電子工程系' and Prof  not in ( select Prof from Teacher where Depart = '計算機系' )

29、查詢選修編號為“3-105“課程且成績至少高於選修編號為“3-245”的同學的Cno、Sno和Degree,並按Degree從高到低次序排序。

any:代表括號中任意一個成績就可以

1
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

30、查詢選修編號為“3-105”且成績高於選修編號為“3-245”課程的同學的Cno、Sno和Degree.

all:代表括號中的所有成績

1
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

31、 查詢所有教師和同學的name、sex和birthday.

1
select tname,tsex,tbirthday from Teacher union select sname,ssex,sbirthday from Student

32、查詢所有“女”教師和“女”同學的name、sex和birthday.

1
select Tname,Tsex,Tbirthday from Teacher where Tsex= '女' union select Sname,Ssex,Sbirthday from Student where Ssex= '女'

33、 查詢成績比該課程平均成績低的同學的成績表。

1
select * from score a  where degree < ( select avg (degree) from score b where b.cno=a.cno)

34、 查詢所有任課教師的Tname和Depart.

1
select Tname,Depart from Teacher where tno in ( select tno from course )

35 、 查詢所有未講課的教師的Tname和Depart.

1
select Tname,Depart from Teacher where Tno not in ( select Tno from Course where cno in ( select cno from score  ))

36、查詢至少有2名男生的班號。

1
select class from student where ssex= '男' group by class having count (*)>1

37、查詢Student表中不姓“王”的同學記錄。

1
select * from Student where Sname not  like '王%%'

38、查詢Student表中每個學生的姓名和年齡。

1
select Sname, year (now())- year (sbirthday)  from Student

39、查詢Student表中最大和最小的Sbirthday日期值。

1
select Max (Sbirthday ), Min (Sbirthday ) from Student

40、以班號和年齡從大到小的順序查詢Student表中的全部記錄。

1
select * from Student  order by  class desc , Sbirthday

41、查詢“男”教師及其所上的課程。

1
select Tname,Cname from course,teacher where course.tno= teacher.tno and teacher.Tsex= '男'

42、查詢最高分同學的Sno、Cno和Degree列。

1
select Sno,Cno,Degree from score where degree=( select max (degree) from score)

排序寫法:

1
select Sno,Cno,Degree from score order by degree desc limit 0,1

43、查詢和“李軍”同性別的所有同學的Sname.

1
select Sname from Student where Ssex = ( select Ssex from Student where Sname= '李軍' )

44、查詢和“李軍”同性別並同班的同學Sname.

1
select Sname from Student where Ssex = ( select Ssex from Student where Sname= '李軍' ) and class=( select class from student where Sname= '李軍' )

45、查詢所有選修“計算機導論”課程的“男”同學的成績表。

1
select  Sno,Cno,degree from score where Cno=( select Cno from course where Cname= '計算機導論' ) and Sno in ( select Sno from student where Ssex= '男' )
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