create database zuoye default charset=utf8;      -- 創(chuàng)建數(shù)據(jù)庫
use zuoye;      -- 使用數(shù)據(jù)庫


#創(chuàng)建幾個庫表
create table Student    -- 學生表
(
Sno char(3) NOT NULL Primary key ,    -- 學號 畸陡，設(shè)為主鍵虽填，不允許空值   
Sname char(8) NOT NULL,        -- 學生姓名
Ssex char(2)NOT NULL,        -- 學生性別
Sbirthday datetime,     -- 學生出生年月
Class char(5)         -- 學生所在班級
);

create table Teacher        -- 教師表
(
Tno char(3)NOT NULL primary key,        -- 教工編號設(shè)為主鍵
Tname char(4)NOT NULL,        -- 教工姓名
Tsex char(2)NOT NULL,        -- 教工性別
Tbirthday datetime,        -- 教工出生年月
Prof char(6),        -- 職稱
Depart varchar(10)NOT NULL        -- 教工所在部門
)

create table Course        -- 課程表
(
    Cno char(5) NOT NULL Primary key ,        -- 課程號設(shè)為主鍵
    Cname varchar(10) NOT NULL,        -- 課程名稱
    Tno char(3) NOT NULL references Teacher(Tno)        -- 教工編號設(shè)為外鍵
)

create table Score    -- 成績表
(
Sno char(3) NOT NULL references Student(Sno),    -- 學號設(shè)為外碼
Cno char(5) NOT NULL references Course(Cno),    -- 課程號設(shè)為外碼
Degree Decimal(4,1),    -- 成績
primary key(Sno,Cno)    -- 學號和課程號設(shè)為聯(lián)合主鍵
)

二、插入數(shù)據(jù)


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');

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');

insert into Course values('3-105','計算機導論',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',831);

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(101,'3-105',64);
insert into Score values(107,'3-105',91);
insert into Score values(108,'3-105',78);
insert into Score values(101,'6-166',85);
insert into Score values(107,'6-166',79);
insert into Score values(108,'6-166',81); 

select * from Student;
select * from Teacher;
select * from Course;
select * from Score;


create table Grade(Low int  ,Upp int,Rank char(1))
select *from Grade;
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');

-- 1、 查詢Student表中的所有記錄的Sname第献、Ssex和Class列兔港。
select sname,ssex,class from student;

-- 2、 查詢教師所有的單位即不重復的Depart列衫樊。  distinct
select distinct depart from teacher;

-- 3、 查詢Student表的所有記錄载佳。
select * from student;

-- 4臀栈、 查詢Score表中成績在60到80之間的所有記錄。    and  
select * from score where degree >60 and degree <80;
select * from score where degree between 60 and 80;

-- 5权薯、 查詢Score表中成績?yōu)?5，86或88的記錄肋联。  or
select cno,degree,sno from score where degree=85 or degree=86 or degree=88;

-- 6刁俭、 查詢Student表中"95031"班或性別為"女"的同學記錄。  or   ||
select class,ssex from student where class=95031 || ssex='女';

-- 7、 以Class降序查詢Student表的所有記錄虑粥。
select * from student order by class desc;

-- 8宪哩、 以Cno升序、Degree降序查詢Score表的所有記錄锁孟。
select* from score order by cno ,degree desc;

-- 9、 查詢"95031"班的學生人數(shù)储笑。
select count(*) from student where class='95031';
select * from student;

-- 10圆恤、 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）
select sno,cno from score  order by degree desc limit 1 ;
select * from score;

-- 10.1 查詢Score表中除了每門課程最高分的學生學號和課程號羽历。（子查詢或者排序） 
select sno,cno from score where degree  !=(select degree from score  order by degree desc limit 1 
)

-- 11淡喜、查詢每門課的平均成績。
select  avg(degree) from score group by cno;
select * from score;

-- 12炼团、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(shù)。
select cno, avg(degree)
from score  where cno like '%3%' 
group by cno
having count(sno)>=5;

-- 13币叹、查詢分數(shù)大于70模狭，小于90的Sno列。
select sno
from score
group by sno
having min(degree)>70 and max(degree)<90;

-- 14嚼鹉、查詢所有學生的Sname、Cno和Degree列匹舞。 
select sname,cno,degree from student join score on student.sno=score.sno
order by student.sno;

-- 15线脚、查詢所有學生的Sno叫榕、Cname和Degree列
select sno,cname,degree from course join score on course.cno=score.cno
order by sno;

-- 16姊舵、查詢所有學生的Sname、Cname和Degree列荞下。
select sname,cname,degree from student join score on student.sno=score.sno join course on score.cno=course.cno
order by student.sno;

-- 17史飞、查詢"95033"班學生的平均分。
select class, avg(degree) from student
join score on student.sno=score.sno
group by class
having class='95033'
order by class

-- 18构资、 現(xiàn)查詢所有同學的Sno、Cno和rank列。
select sno,cno,rank from score join grade on score.degree between grade.low and grade.upp
order by sno;

-- 19塞帐、查詢選修"3-105"課程的,并且成績高于"109"號同學成績的所有同學的記錄。
select *
from student join score on student.sno=score.sno
where cno = '3-105'
group by score.sno
having degree > (select max(degree) from score where score.sno='109');

-- 20荷鼠、查詢成績高于學號為"109"榔幸、課程號為"3-105"的成績的所有記錄。
select *
from score join course on score.cno=course.cno
where course.cno = '3-105'
group by sno
having degree > (select max(degree) from score where sno='109');