设有学生成绩表sc

① 设有以下3个基本表：学生S，成绩SC，课程G

1
insert into s(SNO,SNAME,SAGE) values('990750','钱江',18)
2
update SC set GRADE=null from SC
inner join G on SC.CNO=G.CNO
where CNAME='数学' and GRADE<60
3
select SNO,CNO from SC where GRADE is null
4
select SNO from SC
inner join G on SC.CNO=G.CNO
where TNAME='王老专师属'

② 设有一个教学数据库ecation，包括student、course和sc三个表

create table sc(
sno char(100),
cno char(100),
grade number
);
alter table sc add constraint pk_1 primary key(sno,cno)

alter table sc add constraint sno_1 foreign key(sno) references student(sno)
alter table sc add constraint cno_1 foreign key(cno) references course(cno)
select a.*,b.*,c.grade from student a, course b ,sc c
where a.sno=c.sno and b.cno=c.cno and a.name like'张%'
select a.*,b.*,c.grade from student a, course b ,sc c
where a.sno=c.sno and b.cno=c.cno and a.xi_name in('IS','EB')
select sex,sum(age)/count(*) from student a
group by sex
select a.Stu_no,a.name,b.course_name,c.grade from student a, course b ,sc c
where a.sno=c.sno and b.cno=c.cno
select a.stu_no,c.grade from student a, course b ,sc c
where a.sno=c.sno and b.cno=c.cno and b.cno='1'
order by c.grade desc
alter table student add(inyear char(4))
update sc set grade =60 where grade between 55 and 59
delete sc where sno='200910001'
insert student into
(sno,
name,
sex
)
values
('20110001',
'张小涛',
'男'
)

③ 有四张表：Student 学生表 ，Course 课程表 ，SC成绩表 ，Teacher 教师表，求SQL语句

select sc.* from sc,course where sc.课程号=course.课程号 and course.课程名='3-105' and sc.成绩 between 60 and 80;
select sc.* from sc where sc.成绩 in(85,56,88);
3. 这个有疑问
我的理解是，学生参加了多门考试，所有成回绩都在70-90之间的。答取这部分人的学号。
select 学号 from (select 学号，max(成绩) 最高分，min(成绩) 最低分 from sc group by 学号) a where a.最高分 < 90 and a.最低分 >70

④ 设有学生选课表SC(学号，课程号，成绩),用SQL命令检索

C1、C5在表中是两条记录哦

⑤ 设有表示学生选课的三张表,学生S(学号,姓名,性别,年龄,身份证号),课程C(课号,课名),选课SC(学号,课号,成绩

以下图为例

学号 课号 成绩
X1 K1 90
X1 K2 90
X1 K3 90

X2 K1 90
X2 K2 90
X2 K3 90

X3 K1 90
X3 K3 90

则会发现 学号+课号 具有唯一性（键或码的充要条件）回，单独的学号或者课答号也不具有唯一性，所以不能单独作为键或码。 同时注意，图中成绩都为90分的话，那么成绩在该表讨论 键或码 的问题中是没有意义的。如果成绩改成排名的话，并且强制排名只能具有唯一性的话，排名就可以单独成为 键或码。

判断键或码的时候主要是看是否具有唯一性。

所以 C

⑥ SQL语句执行问题：有一张表sc如下：查询每位学生的最高成绩。

对于每个学号，不存在比这个学号的分数低的数据全部查出来。
反之就是得到每个学号最高的分数了。

另外，你也可以

select sno,max(grade) from sc group by sno

⑦ 设有学生课程表SC（学号，课程名，成绩）用SQL检索同时选修课程号为"C1"和"C5"的学生的学号的正确命令是

你那个是永远为假的，一个课程号怎么可能同时为2个值呢，可以这样写

SELECT 学号内
FROM SC
WHERE 课程容号 IN ('C1', 'C5')
GROUP BY 学号
HAVING COUNT(DISTINCT 课程号) = 2

或者
SELECT 学号
FROM SC t1
WHERE 课程号 = 'C1'
AND EXISTS (SELECT 1 FROM SC WHERE 学号 = t1.学号 AND 课程号 = 'C5')

⑧ 假设在教务管理系统数据库中有学生Student、课程关系Course、选修关系SC、试用关系代数表示下列查询。

从学生，当然1。选择姓名，成绩在那里（student.学生数=得分。学生证）和（版course.课程名称=得分。权课程名称）和（score.学期= '02-03/1'）和（ coourse。课程名=数据结构）
2。无法查询，因为没有老师的名字字段。

从学生，当然，得分3。选择名称，其中（student.学生数=得分。学生证）和（course.课程名称=得分。课程名称），并得分。成绩> =（选择

4。说每门课检查出那些谁得分最高等级的名称

5，从学生删除，成绩在那里的学生。学号=得分。学号和成绩。得分= 0
6。更新设置得分得分。得分=得分。分数*（1 +0.05），其中（course.课程名=得分。课程名称），当然，课程号= 02和（score.分数< AVG（score.分数））

⑨ 有四张表：Student 学生表 ，Course 课程表 ，SC成绩表 ，Teacher 教师表，求SQL语句

把表结构发来，我给你写

⑩ SQL语句的一道题 三个基本表：学生表(Student)、课程表（Course）、学生选课表（SC）

1. select * from SC
2. select Sname，Sage from Student where Sdept = '计算机'
3. select Sno,Cno,Grade from SC where Grade >= 70 and Grade <= 80
4. select Sname,Sage from Student where Sage between 18 and 20 and Ssex = '男'
5. select top 1 Grade from SC where Cno = 'C01'
6. select max(Sage),min(Sage) from Student
7. select Sdept,sum(Sno) from Student group by Sdept
8. select course.Cname,sum(sc.Sno),max(Grade) from SC
join studet on Student.Sno = SC.Sno
join Course on Course.Cno = SC.Cno
group by course.cname,max(grade)

9. select sum(Cno),avg(Grade) from SC
join Course on Course.Cno = SC.Cno
join Student on Student.Sno= SC.Sno
order by SC.Sno

10. select Stuent.Sno，Stuent.Sname，sum(Grade) A from SC
join Student on Student.Sno = SC.Sno
group by sc.Sno,student.Sname
having A > 200

11. select Student.Sname,Student.Sdept from Student
join Course on Course.Cno = SC.Cno
join SC on SC.Sno = Student.Sno
where SC.Cno = 'C02'

12. select Student.sname,course.cno,sc.grade from sc
join student on student.sno = sc.sno
join course on course.cno = sc.cno
where sc.grade >= 80
order by sc.grade desc

13. select cno,cname from
(
select course.cno,course.cname,sun(sno) from student
join course on course.cno = sc.cno
join sc on sc.sno = student.sno
group by cno,cname
having sun(sno) > 0
)

14. ① select student.sname,student.sdept from
(
select student.sname,student.sdept,course.cname from student
join sc on sc.sno = student.sno
join course on course.cno = sc.cno
where course.cname = 'C01'
)

② select student.sno,student.sname from
(
select student.sno,student.sname,student.sdept,sc.grade from sc
join student on student.sno = sc,sno
where student.sdept = '信息' and sc.grade >= 80
)

③ select top 1 student.sname from
(
select student.sname,student.sdept,sum(sc.grade) from sc
join student on student.sno = sc.sno
where student.sdept = '计算机'
group by student.sname,student.sdept
order by
)

15. delete from sc where grade < 50
16. update sc set grade += 5 from sc
join course on course.cno = sc.cn
join student on student.sno = sc.sno
where student.sno =
(
select student.sno from sc
join course on course.cno = sc.cno
where course.cname = 'c01'
)

17. update sc set grade += 10 from sc
join student on student.sno = sc.sno
where student.sno =
(
select student.sno from student
join sc on sc.sno = student.sno
join course on course.cno = sc.cno
where student.sdept = '计算机' and course.cname = '计算机文化基础'
)

18. create view [A] as
select student.sno,student.sname,student.sdept,course.cno,course.cname,sc.grade from sc
join student on student.sno = sc.sno
join course on course.cno = sc.cno

19. create view [A] as
select student.sno,avg(sc.grade) from sc
join student on student.sno = sc.sno
group by student.sno

20. create view [A] as
select student.sno,sum(sc.grade) from sc
join student on student.sno = sc.sno
group by student.sno

21. create index A on student(sname)
22. 不会