MySQL查询语句的45道练习
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語句創建四個表并完成相關題目。
???????????????? 表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) | 否 | 學號（主碼） |
| Sname | varchar (20) | 否 | 學生姓名 |
| Ssex | varchar (20) | 否 | 學生性別 |
| Sbirthday | datetime | 可 | 學生出生年月 |
| Class | varchar (20) | 可 | 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) | 否 | 課程號（主碼） |
| Cname | varchar (20) | 否 | 課程名稱 |
| Tno | varchar (20) | 否 | 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) | 否 | 學號（外碼） |
| Cno | varchar (20) | 否 | 課程號（外碼） |
| Degree | Decimal(4,1) | 可 | 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) | 否 | 教工編號（主碼） |
| Tname | varchar (20) | 否 | 教工姓名 |
| Tsex | varchar (20) | 否 | 教工性別 |
| Tbirthday | datetime | 可 | 教工出生年月 |
| Prof | varchar (20) | 可 | 職稱 |
| Depart | varchar (20) | 否 | 教工所在部門 |
表1-2數據庫中的數據
表（一）Student
| Sno | Sname | Ssex | Sbirthday | class |
| 108 | 曾華 | 男 | 1977-09-01 | 95033 |
| 105 | 匡明 | 男 | 1975-10-02 | 95031 |
| 107 | 王麗 | 女 | 1976-01-23 | 95033 |
| 101 | 李軍 | 男 | 1976-02-20 | 95033 |
| 109 | 王芳 | 女 | 1975-02-10 | 95031 |
| 103 | 陸君 | 男 | 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 | 男 | 1958-12-02 | 副教授 | 計算機系 |
| 856 | 張旭 | 男 | 1969-03-12 | 講師 | 電子工程系 |
| 825 | 王萍 | 女 | 1972-05-05 | 助教 | 計算機系 |
| 831 | 劉冰 | 女 | 1977-08-14 | 助教 | 電子工程系 |
?
#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名學生選修的并以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、???? 查詢分數大于70，小于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”課程的成績高于“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 | 選了多門課程并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、查詢成績高于學號為“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于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“課程且成績至少高于選修編號為“3-245”的同學的Cno、Sno和Degree,并按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”且成績高于選修編號為“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”同性別并同班的同學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') |
轉載于:https://www.cnblogs.com/wu-chao/p/9071822.html
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