個(gè)人筆記，僅供參考

查詢練習(xí)數(shù)據(jù)準(zhǔn)備

準(zhǔn)備數(shù)據(jù)供下文使用
1、學(xué)生表(student)

學(xué)號(hào)，姓名，性別，出生年月日，班級(jí)

mysql> create table student(
    -> sno varchar(20) primary key,
    -> sname varchar(20) not null,
    -> ssex varchar(20) not null,
    -> sbirthday datetime,
    -> class varchar(20)
    -> );

2、課程表(course)

課程號(hào)，課程名稱，教師編號(hào)

mysql> create table course(
    -> cno varchar(20) primary key,
    -> cname varchar(20) not null,
    -> tno varchar(20) not null,
    -> foreign key(tno) references teacher(tno)
    -> );

3、成績(jī)表(score)

學(xué)號(hào)，課程號(hào)，成績(jī)

mysql> create table score(
    -> sno varchar(20) not null,
    -> cno varchar(20) not null,
    -> degree decimal,
    -> foreign key(sno) references student(sno),
    -> foreign key(cno) references course(cno),
    -> primary key(sno,cno)
    -> );

4、教師表(teacher)

教師編號(hào)，教師姓名。教師性別，出生年月日，職稱，所在部門

mysql> create table teacher(
    -> tno varchar(20) primary key,
    -> tname varchar(20) not null,
    -> tsex varchar(10) not null,
    -> tbirthday datetime,
    -> prof varchar(20) not null,
    -> depart varchar(20) not null
    -> );

往數(shù)據(jù)表中添加數(shù)據(jù)

1、在學(xué)生表中添加以下數(shù)據(jù)

insert into student values('188','曾華','男','1997-09-01','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');

2、教師表

insert into teacher values('804','李誠(chéng)','男','1958-12-02','副教授','計(jì)算機(jī)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(jì)算機(jī)系 ');
insert into teacher values('831','劉冰','女','1977-08-14','助教','電子工程系');

3、課程表

insert into course values('3-105','計(jì)算機(jī)導(dǎo)論','825');
insert into course values('3-245','操作系統(tǒng)','804');
insert into course values('6-166','數(shù)字電路','856');
insert into course values('9-888','高等數(shù)學(xué)','831');

4、成績(jī)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','6-166','85');
insert into score values('105','6-166','79');
insert into score values('109','6-166','81');

查詢練習(xí)

1、查詢student表的所有信息

select * from student;

2、查詢student表中的所有記錄的sname，ssex和class列

select sname, ssex, class from student;

3、查詢教師所有的單位，即不重復(fù)的depart列

select distinct depart from teacher; 

4、查詢score表中成績(jī)?cè)?0到80之間的所有記錄

使用between...and...

select * from score where degree between 60 and 80;

或者使用運(yùn)算符

select * from score where degree > 60 and degree < 80;

5、查詢score表中成績(jī)?yōu)?5、86或88的記錄

表示或者關(guān)系，in

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(xué)記錄

使用or

select * from student where class='95031' or ssex='女';

7、以class降序查詢student表的所有記錄

升序(asc)，降序(desc) 默認(rèn)為升序

select * from student order by class desc;

8、以con升序、degree降序查詢score表的所有記錄

即以cno升序排列，遇到相同的再以degree降序排列

select * from score order by cno asc,degree desc;

9、查詢“95031”班的學(xué)生人數(shù)

統(tǒng)計(jì)count

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

10、查詢score表中的最高分的學(xué)生學(xué)號(hào)和課程號(hào)。（子查詢或排序）

select sno,cno from score where degree=(select max(degree) from score);