学生表（Student）、课程表（Course）、成绩表（Score）以及教师信息表（Teacher）。四个表的结构分别如表1-1的表（一）~表（四）所示，数据如表1-2的表（一）~表（四）所示。用SQL语句创建四个表并完成相关题目。
表1-1数据库的表结构
表（一）Student (学生表)
|
属性名 |
数据类型 |
可否为空 |
含 义 |
|
Sno |
varchar (20) |
否 |
学号（主码） |
|
Sname |
varchar (20) |
否 |
学生姓名 |
|
Ssex |
varchar (20) |
否 |
学生性别 |
|
Sbirthday |
datetime |
可 |
学生出生年月 |
|
Class |
varchar (20) |
可 |
学生所在班级 |
表（二）Course（课程表）
|
属性名 |
数据类型 |
可否为空 |
含 义 |
|
Cno |
varchar (20) |
否 |
课程号（主码） |
|
Cname |
varchar (20) |
否 |
课程名称 |
|
Tno |
varchar (20) |
否 |
教工编号（外码） |
表（三）Score(成绩表)
|
属性名 |
数据类型 |
可否为空 |
含 义 |
|
Sno |
varchar (20) |
否 |
学号（外码） |
|
Cno |
varchar (20) |
否 |
课程号（外码） |
|
Degree |
Decimal(4,1) |
可 |
成绩 |
|
主码：Sno+ Cno |
|||
表（四）Teacher(教师表)
|
属性名 |
数据类型 |
可否为空 |
含 义 |
|
Tno |
varchar (20) |
否 |
教工编号（主码） |
|
Tname |
varchar (20) |
否 |
教工姓名 |
|
Tsex |
varchar (20) |
否 |
教工性别 |
|
Tbirthday |
datetime |
可 |
教工出生年月 |
|
Prof |
varchar (20) |
可 |
职称 |
|
Depart |
varchar (20) |
否 |
教工所在部门 |
表1-2数据库中的数据
表（一）Student
|
Sno |
Sname |
Ssex |
Sbirthday |
class |
|
108 |
曾华 |
男 |
1977-09-01 |
95033 |
|
105 |
匡明 |
男 |
1975-10-02 |
95031 |
|
107 |
王丽 |
女 |
1976-01-23 |
95033 |
|
101 |
李军 |
男 |
1976-02-20 |
95033 |
|
109 |
王芳 |
女 |
1975-02-10 |
95031 |
|
103 |
陆君 |
男 |
1974-06-03 |
95031 |
表（二）Course
|
Cno |
Cname |
Tno |
|
3-105 |
计算机导论 |
825 |
|
3-245 |
操作系统 |
804 |
|
6-166 |
数字电路 |
856 |
|
9-888 |
高等数学 |
831 |
表（三）Score
|
Sno |
Cno |
grade |
|
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 |
李诚 |
男 |
1958-12-02 |
副教授 |
计算机系 |
|
856 |
张旭 |
男 |
1969-03-12 |
讲师 |
电子工程系 |
|
825 |
王萍 |
女 |
1972-05-05 |
助教 |
计算机系 |
|
831 |
刘冰 |
女 |
1977-08-14 |
助教 |
电子工程系
|
-- 查询Student表中的所有记录的Sname、Ssex和Class列。
SELECT Sname,Ssex,Class from student
-- 查询教师所有的单位即不重复的Depart列。
SELECT distinct Depart from teacher
-- 查询Student表的所有记录。
SELECT * from student
-- 查询Score表中成绩在60到80之间的所有记录。
SELECT * from Score where grade>60 and grade<80
-- 查询Score表中成绩为85，86或88的记录。
SELECT * from Score where grade in (85,86,88)
-- 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=false
-- 以Class降序查询Student表的所有记录。
SELECT * from Student order by Class desc
-- 以Cno升序、Degree降序查询Score表的所有记录。
SELECT * from score order by Cno asc,grade desc
-- 查询“95031”班的学生人数。
SELECT count(*) from student where Class = '95031'
-- 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
SELECT * from score order by grade desc
-- 查询每门课的平均成绩。
SELECT Cno, avg(grade) from score group by Cno
-- 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。
SELECT Cno , avg(grade) from score where Cno like '3%' group by Cno having count(Sno)>=5
SELECT avg(grade) from score where Cno in(
SELECT Cno from score where Cno like '3%'
and
Cno in(
SELECT Cno from score group by Cno having count(Sno)>=5
)
)
group by Cno
-- 查询分数大于70，小于90的Sno列。
SELECT Sno from score where grade>70 and grade<90
-- 查询所有学生的sname、cno和degree列
SELECT Sname,Cno,grade from score join student on score.Sno=student.Sno
-- 查询所有学生的sno、sname和degree列
SELECT Sno,Cname,grade from score join course on score.Cno=course.Cno
-- 查询所有学生的sname、cname和degree列
SELECT Sname,Cname,grade from score join student on score.Sno=student.Sno
join course on score.Cno=course.Cno
SELECT Sname,Cname,grade from student,course,score where score.Cno=course.Cno and
score.Sno=student.Sno
-- 查询“95033”班学生的平均分
SELECT avg(grade) from score join student on score.Sno=student.Sno where class="95033"
--
-- 使用下面命令建立一个grade表
create table grad (
low int (3),
upp int (3),
rank char (1)
)
insert into grad values (90,100,'A')
insert into grad values (80,89,'B')
insert into grad values (70,79,'C')
insert into grad values (60,69,'D')
insert into grad values (0,59,'E')
-- 查询所有同学的sno、cno和rank列
SELECT Sno,Cno,rank from score,grad where grade between low and upp
-- 查询选修3-105课程的成绩高于109号同学成绩的所有同学的记录
SELECT grade from score where Cno='3-105' and grade>(
SELECT grade from score where Sno=109 and Cno='3-105'
)
-- 查询score中选修多门课程的同学中分数为非最高分成绩的记录
SELECT sum(grade) from score group by Sno having count(Sno)>=2
order by sum(grade) desc
SELECT sum(grade) from score where Sno in(
SELECT Sno from score group by Sno having count(Sno)>=2
)
group by Sno-- 分组求和，否则求出总数
-- 查询成绩高于学号为109、课号为3-105 的成绩的所有记录
SELECT * from score where grade>(
SELECT grade from score where Sno=109 and Cno='3-105'
)
-- 查询京津教师任课的学生成绩
SELECT grade from score where Cno in(
SELECT Cno from course where Tno in(
SELECT Tno from teacher where Tname='京津'
)
)
SELECT grade from score join course on score.Cno=course.Cno
join teacher on course.Tno=teacher.Tno where Tname='京津'
--查询选修某课程的同学人数多于5人的教师姓名
SELECT Tname from teacher where Tno in(
SELECT Tno from course where Cno in(
SELECT Cno from score group by Cno having count(Sno)>=5
)
)
-- group by Cno
-- 查询95033班和95031班全体学生的记录
SELECT * from score where Sno in(
SELECT Sno from student where class in(95033,95031)
)
-- 查询存在有85分以上成绩的课程Cno
SELECT distinct Cname from course join score on course.Cno=score.Cno
where grade>=85
SELECT distinct Cno from score where grade>=85
-- 查询出 计算机系 教师所教课程的成绩表
SELECT grade from score where Cno in(
SELECT Cno from course where Tno in(
SELECT Tno from teacher where Depart='计算机系'
)
)
SELECT grade from score join course on score.Cno=course.Cno
join teacher on course.Tno=teacher.Tno
where Depart='计算机系'
-- 查询计算机系与电子工程系不同职称的Tname和Prof教师的
SELECT Tname,Prof from teacher where Depart='计算机系' and Prof not in (
SELECT prof from teacher where Depart='电子工程系'
)
union all
SELECT Tname,Prof from teacher where Depart='电子工程系' and Prof not in (
SELECT prof from teacher where Depart='计算机系'
)
SELECT Tname,Prof from teacher a where Prof
not in (SELECT Prof from teacher b where a.Depart != b.Depart)
-- 查询选修编号为“3-105“课程且成绩至少高于选修编号
-- 为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
SELECT * from score where Cno='3-105'
and grade >
any(SELECT grade from score where Cno='3-245'
)
order by grade asc
-- all 所有，any 任意
-- 查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
SELECT * from score where Cno='3-105'
and grade >
(SELECT max(grade) from score where Cno='3-245'
)
-- 查询所有教师和同学的name、sex和birthday.
SELECT Tname,sex from teacher
union all
SELECT Sname,Ssex from student
-- 查询所有“女”教师和“女”同学的name、sex和birthday.
SELECT Tname,sex from teacher where sex=0
union all
SELECT Sname,Ssex from student where Ssex=0
-- 查询成绩比该课程平均成绩低的同学的成绩表。
SELECT * from score where Cno='3-245' and grade<
(SELECT avg(grade) from score where Cno='3-245'
)
union
SELECT * from score where Cno='3-105' and grade<
(SELECT avg(grade) from score where Cno='3-105'
)
union
SELECT * from score where Cno='6-116' and grade<
(SELECT avg(grade) from score where Cno='6-116'
)
SELECT * from score join (SELECT Cno,avg(grade) as a from score group by Cno) as b on
(b.Cno=score.Cno) where grade<a
Select * from score a where grade<(select avg(grade) from score b where a.cno=b.cno)
-- 查询所有任课教师的Tname和Depart.
SELECT Tname,Depart from teacher where Tno in(
SELECT Tno from course where Cno in(
SELECT Cno from score group by Cno
)
)
--查询所有未讲课的教师的Tname和Depart.
SELECT Tname,Depart from teacher where Tno not in(
SELECT Tno from course where Cno in(
SELECT Cno from score group by Cno
)
)
SELECT Tname,Depart from teacher where Tno not in(
SELECT Tno from course where Cno in(
SELECT distinct Cno from score
)
)
-- 查询至少有2名男生的班号。
SELECT distinct class from student where Ssex in(
SELECT Ssex from student where Ssex=1 and Ssex in(
SELECT Ssex from student group by Ssex having count(Ssex)>=2
)
)
SELECT class from student where Ssex='1' group by class having count(*)>=2
-- 查询Student表中不姓“王”的同学记录。
SELECT * from student where Sname not like '王%'
-- 查询Student表中每个学生的姓名和年龄。
SELECT Sno,Sname from student
alter table student add column birthday varchar(30);
select sname as '姓名',(year ( date ( now() )) - year(birthday) ) as '年龄' from student;
select sname,(year(date(now()) ) -year(birthday) ) from student;
-- 查询Student表中最大和最小的Sbirthday日期值。
SELECT max(Sno)from student
union
SELECT min(Sno)from student
SELECT max(Sno) as '最大值',min(Sno) '最小值' from student
--以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT * from student order by class desc,Sno desc
-- 查询“男”教师及其所上的课程。
SELECT Cname from course where Tno in(
SELECT Tno from teacher where sex=1
)
-- 查询最高分同学的Sno、Cno和Degree列。
SELECT Sno,Cno,grade from score where grade in(
SELECT max(grade) from score
)
--查询和“李军”同性别的所有同学的Sname.
SELECT Sname from student where Ssex in (
SELECT Ssex from student where Sname='张三'
)
--查询和“李军”同性别并同班的同学Sname.
SELECT Sname from student where class in (
SELECT class from student where Sname='张三'
)
and
Ssex in(
SELECT Ssex from student where Sname='张三'
)
--查询所有选修“计算机导论”课程的“男”同学的成绩表。
SELECT grade from score where Cno in(
SELECT Cno from course where Cname='计算机导论'
)
and
Sno in(
SELECT Sno from student where
Ssex in(
SELECT Ssex from student where Ssex=1
)
)