有点不明白这几道题。。。

(19)
Select     StudentID
from       SC
where      CourseID = (select CourseID from C where CourseName ='Data Structure')
           and
           StudentID in
           (
                Select     StudentID
                from      SC
                where     CourseID = (select CourseID from C where CourseName ='C Language')
           )

(20)
select    S.StudentID, S.StudentName, S.Department
from      SC join S on SC.StudentID = S.StudentID
where     SC.CourseID = 'C02'

(21)
select    distinct S.StudentID, S.StudentName, S.Department
from      SC join S on SC.StudentID = S.StudentID
where     SC.CourseID = 'C01'  OR
          SC.CourseID = 'C02'


(22)
Select     S.StudentName
from       SC join S on SC.StudentID = S.StudentID
where      SC.CourseID = 'C01'
           and
           SC.StudentID in
           (
               Select     StudentID
               from       SC
               where      CourseID = 'C02'
            )

(23)
select     StudentID, StudentName, datediff(yy,BirtherDate, getdate()) as Age
from       S

(24)
select     StudentName as Student_Name, year(Birtherdate) as Birth_Year
from       S

(28)
select       S.StudentID, S.StudentName, count(*) as TotalCourseNumbers
from         SC join S on SC.StudentID = S.StudentID
group by     S.StudnetID, S.StudentName
having       count(*) > 3

[ 本帖最后由 png 于 2011-6-27 22:43 编辑 ]