用数据库的语言,查询备注为空的教师的信息。

select * from 表名 where 备注=null

看到楼下想起来，null不能用等于判断，可以用is

select * from 表名 where 备注 is null

发我邮箱[email protected]

9.检索XK数据库的COURSE表的课程信息,要求显示报名人数与限选人数之比.

select *,WillNum/LimitNum as rate from Course

10. 检索课程表中最小的报名人数、最大的报名人数以及平均报名人数.

select min(WillNum) as a,max(WillNum) as b,avg(WillNum) as c from Course

11.检索课程信息(包括报名人数与限选人数之比),要求检索结果按照报名人数升序排序.

select *,WillNum/LimitNum as rate from Course

order by WillNum

26.按课程分类统计平均报名人数.

select kind,avg(WillNum) as '平均数' from Course

group by Kind

27.检索”信息技术”类课程的平均报名人数.

select avg(WillNum) as '平均数' from Course

where Kind='信息技术'

28.检索平均报名人数大于25人的课程分类和类平均报名人数.

select Kind,avg(WillNum) from Course

group by Kind

having avg(WillNum)>25

29.检索报名人数大于平均报名人数的课程编码,课程名称,报名人数.

select CouNO,CouName,WillNum from Course

where WillNum>(select avg(WillNum) as '平均数' from Course)

30.从班级表中检索班级名，从系表中检索系部名称,使用UNION运算符合并上面两个结果.

select ClassName from Class

UNION

select DepartName from Department

25.按类显示课程表的课程编码,课程名称,课程分类,报名人数,并计算每类平均报名人数.

select a.couno,a.couname,a.kind,b.avg_wn

from course a,(select kind,avg(willnum) as avg_wn from course group by kind) b

where a.kind=b.kind

order by a.kind

你的意思是建一个教师基本信息表吧！CREATETABLE[tbTeacherInfo]--教师信息表([t_id][int]IDENTITY(1,1)NOTNULL,--教师的编号，唯一的标识[t_Name][varchar](50)NOTNULL,--教师的姓名[t_identification][varchar](50)NOTNULL,--身份z号码[t_Birth][varchar](50)NOTNULL,--出生日期[t_Sex][varchar](50)NOTNULL,--性别[t_Age][varchar](50)NOTNULL,--年龄[t_GraduateSchool][varchar](50)NOTNULL,--毕业学校[t_Mobile][varchar](50)NOTNULL,--联系电话[t_Address][varchar](50)NOTNULL,--通讯地址[t_E-mail][varchar](50)NOTNULL,--E-Mail[t_Specialty][varchar](50)NOTNULL,--专业[t_Folk][varchar](50)NOTNULL--民族)GO基本信息就是这样的

---