课程表包括哪些字段

1. 假设当前有课程表,课程表的结构包括(课程名,学时,学分),删除课程表中的学时字段

在命令窗口中输入
alter table 课程 drop column 学时
如果提示找不到表,可以先输入set defa to 表所在路径
如set defa to d:\练习1
或者用菜单,选择"文件|打开",文件类型选"表",把课程表打开,然后选择菜单"显示|表设计器",选中"学时",然后单击"删除"按钮.

2. 一张课表的数据库，包含哪些表和哪些字段

看你课表的设置，一般有：序号，课程名称，课时，授课老师，时间等

3. sql 提问 查询选课表中同一个学生选择多门课的学生信息,选课表有学号,姓名,课目,成绩等字段.没有主健.

你是不是要把选择了多门课的学生以
001 语文，数学
002 语文，数学，英语
这样的格式查询出来，如果只选择一门的要不要查询出来，如果是这样的话，你给我留言，可以写出来的。不过要给点分哦。

4. 使用SQI语句创建三张表（学生表，课程表和成绩表）字段分别是（学号，姓名，年龄，性别，系部，课程号

1、select 姓名 from 学生表 where 系别 = '计算机系'; 2、select 学号 from 学生选课专表 where 成绩 < 60 ; 3、select 学号,成绩 from 学生选课表 where 课程属号=1; 4、select 学生表.姓名,学生选课表.课程号,学生选课表.成绩 from 学生表,学生选课表 where 学生表.学号 = 学生选课表.学号; 5、select 姓名,年龄,性别 from 学生表 where 年龄 > (select 年龄 from 学生表 where name = '李明');

5. 设在学生数据库中有三张表，表结构如下所示： Student(学生表): Student表的主键：sno(学号) Course(课程

(1) create table S_C
(sno char(10) not null
,cno char(8) not null
,score int null
,constraint PK_SC primary key (sno,cno)
)
(2)insert into Student (sno,sname,ssex)
values('1010','李小丽','女')
(3)create index IND_CName on Course (cname)
(4)update student set sage=23 where sno='1005'
(5)delete from course where cname='管理信息系统'
(6)select cno,cname,ctime
from course
where teacher='李元'
order by cno ASC
(7)select sno,sum(score) as score
from S_C
group by sno
(8)create view V_Student
as
select *
from student
where ssex='男' and sage>=18 and sage<=24
(9)select sno,sname
from student
where sno in (select sno from S_C where cno='001')
(10)select A.sno,A.sname
from student A
left join S_C B on A.sno=B.sno
left join Course C on B.cno=C.cno
where C.cname='关系数据库'
(11)select sno,sname from
(select A.sno,A.sname,count(1) as count_
from student A
left join S_C B on A.sno=B.sno
group by A.sno,A.sname) A
where count_>3
(12)select C.sname
from
(select * from S_C where cno='002') A
inner join
(select * from S_C where cno='004' on) B on A.sno=B.sno
left join student C on A.sno=C.sno

6. 用查询语句在课程表中统计所有课程的总学时 结果只包含总学时字段 怎么写

select sum(学时) as 总学时 from 课程表

7. SQL命令 “学生”数据库中有 “学生表”、“课程表”和 “成绩表”。 “学生表”中包含学号、姓名

1、首先在电脑上打开数据库软件。然后附加有学生表和成绩表的数据库。

8. 用SQL创建一个学生表，课程表，学生成绩表

第一个表是学生表Student，包含三个字段，学生id（_id） 和 学生姓名（stu_name）和课程id（les_id）
Create Table [dbo].Student(
stu_id [uniqueidentifier] NOT NULL,
stu_name [nvarchar](425) NOT NULL,
les_id [uniqueidentifier] NOT NULL
)
第二个表课程表Lesson，两个字段，课程id（les_id）和课程名称（les_name）
Create Table [dbo].Lesson(
les_id [uniqueidentifier] NOT NULL,
les_name [nvarchar](425) NOT NULL
)
第三个表学生成绩表Score,三个字段课程id（les_id），学生id（stu_id）和课程得分（les_score）
Create Table [dbo].Score(
les_id [uniqueidentifier] NOT NULL,
stu_id [uniqueidentifier] NOT NULL,
les_score [int] NOT NULL
)

9. 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

10. mysql 课表表的时间段可以修改，用单独的表来维护，字段包括id，begin_time，end

我有books 和 info 表... books表中有 ISBN Allbooks BorrowsBooks info 表有 ISBN Userno Yesorno 当我的 Yesorno 是 YES 时就从BorrowBooks中减去1； 这个触发器我已经写好了。可有个问题...就是当我Yesorno为Yes时.. books表中的每列Borrowbooks都减去1.。 我的触发器代码如下.. CREATE TRIGGER `chu` BEFORE INSERT ON `info` FOR EACH ROW BEGIN IF new.Yesorno='Yes' then UPDATE books SET Borrowbooks=Borrowbooks-1 ; else UPDATE books SET Borrowbooks=Borrowbooks+1 ; end if; END;; 就是update后面的where语句怎么写？？？让他减去的是你info表中写的ISBN号对应books表ISBN号后面的BorrowBooks数...