2018年7月11日笔记
1.新建数据库
设有一个数据库，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）。用SQL语句创建四个表并完成相关题目。
创建学生表
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)
) engine = innodb default charset = utf8;
创建教师表
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
)engine = innodb default charset = utf8;
创建课程表
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)
) engine = innodb default charset = utf8;
创建成绩表
create table score(
sno varchar(20) not null,
foreign key(sno) references student(sno),
cno varchar(20) not null,
foreign key(cno) references course(cno)
degree decimal,
) engine = innodb default charset = utf8;
2.插入数据库
插入学生表数据
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);
插入教师表数据
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');
插入课程表数据
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' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,831);
插入成绩表数据
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,'9-888',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
3.查询数据
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 depart from teacher group by depart;
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。(between)
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。(in)
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。(排序)
select sno,cno from score order by degree desc;
11、查询每门课的平均成绩。(group by)
select cname,avg(degree) from score inner join course where course.cno = score.cno group by course.cname;
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。(group by having)
select cno,avg(degree) from score where cno like "3%" group by cno having count(sno) >= 5;
13、查询最低分大于70，最高分小于90的Sno列。
select sno from score group by sno having max(degree) < 90 and min(degree) > 70 ;
14、查询所有学生的Sname、Cno和Degree列。
select sname,score.cno,degree from student inner join score where student.sno = score.sno;
15、查询所有学生的Sno、Cname和Degree列。
select student.sno,sname,degree from student inner join score where student.sno = score.sno;
16、查询所有学生的Sname、Cname和Degree列。
select sname,cname,degree from student inner join score,course on student.sno = score.sno and course.cno = score.cno;
17、查询“95033”班学生的平均分。(选)
select avg(degree) from student inner join score where class = '95033' and student.sno = score.sno;
18、假设使用如下命令建立了一个grade表,查询所有同学的Sno、Cno和rank列。
create table grade(low int(3),high int(3),rank varchar(20));
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');
commit;
select sno,cno,rank from score inner join grade where degree < high and degree >low;
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。(选)
select * from score where degree > (select degree from score where sno = '109' and cno ='3-105');
20、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。(选)
select sno,sname,sbirthday
from student,(select year(sbirthday) as birthyear from student where sno = 108) as s1
where year(sbirthday) = s1.birthyear;
21、查询“张旭“教师任课的学生成绩。(选)
select tname,cname,sname,degree
from teacher,course,student,score
where teacher.tno = course.tno and course.cno = score.cno and score.sno = student.sno and teacher.tname = '张旭';
22、查询95033班和95031班全体学生的记录。(in)
select * from student where class in ('95033','95031');
23、查询存在有85分以上成绩的课程Cno.
select cno from score group by cno having max(degree) >= 85;
24、查询出“计算机系“教师所教课程的成绩表。(选)
select score.sno,sname,degree
from teacher,score,course,student
where teacher.tno = course.tno and course.cno = score.cno and score.sno = student.sno and teacher.depart = '计算机系';
25、查询成绩比该课程平均成绩低的同学的成绩表。(选)
select s.sno,s.cno,s.degree
from score as s,(select cno,avg(degree) as avgd from score group by cno ) as avgs
where s.cno = avgs.cno and s.degree < avgs.avgd;
26、查询所有任课教师的Tname和Depart.(选)
select tname,depart from teacher;
27、查询至少有2名男生的班号。(group by having)
select class,count(name) from student group by class having count(name) >= 2;
28、查询Student表中不姓“王”的同学记录。(not like)
select * from student where sname not like "王%";
29、查询Student表中每个学生的姓名和年龄。
select sname,2018 - year(sbirthday) as age from student;
30、查询Student表中最大和最小的Sbirthday日期值。
select max(sbirthday),min(sbirthday) from student;
31、以班号和年龄从大到小的顺序查询Student表中的全部记录。
下面两种SQL语句一样的效果，年龄大则出生日期小
select * from student order by class desc,sbirthday;
select * from student order by class desc,sbirthday asc;
32、查询“男”教师及其所上的课程。
select tname,cname from teacher,course where teacher.tno = course.tno and tsex = '男';
33、查询每一门科目最高分同学的Sno、Cno和Degree列。(选)
select sno,cno,max(degree) from score group by cno ;
