求助！！：：SQL语句查询求改正！！

Question

我有一个SQL Server表，表明为：EvaluateTeacherGrade
运行效果如下图：


问题1：我想查询得到所有courseID=200002和teacherID=22222001的相关数据表。我用如下SQL语句查询获得的表count应该等于108才对，但是为什么等？？
SQL语句如下所示：

 select C.courseID,C.courseName,C.teacherID,C.teacherName,Count(e.Grade) As count 
from EvaluateTeacherGrade e,Course C,Grade G 
where e.courseID=G.courseID and e.courseID=C.courseID and e.courseID='200002'and  e.teacherID='22222001' 
GROUP BY C.COURSEID,C.COURSENAME,C.TEACHERID,C.TEACHERNAME

效果图如下所示：

我该如何改正SQL语句啊？？
问题2：我想查询得到所有courseID=200002和studentID=0711001的相关数据表。我用如下SQL语句查询获得的表count应该等于54才对，但是为什么等于45呢？？
SQL语句如下所示：

select C.courseID,C.courseName,C.teacherID,C.teacherName,Count(e.Grade) As count ,e.studentID ,s.studentName 
from EvaluateTeacherGrade e,Course C,Grade G,student s 
where e.courseID=G.courseID and C.courseID=G.courseID and e.studentID =s.studentID 
 and e.courseID='200002'and e.studentID='0711001' 
GROUP BY C.COURSEID,C.COURSENAME,C.TEACHERID,C.TEACHERNAME ,e.studentID ,s.studentName

查询得到的效果图如下所示：

我该如何改正SQL语句呢？？

Answer 1

用以下sql试试
select C.courseID,C.courseName,C.teacherID,C.teacherName,Count(e.Grade) As count
from EvaluateTeacherGrade e,Course C,Grade G
where e.courseID*=G.courseID and e.courseID*=C.courseID and e.courseID='200002'and e.teacherID='22222001'
GROUP BY C.COURSEID,C.COURSENAME,C.TEACHERID,C.TEACHERNAME

select C.courseID,C.courseName,C.teacherID,C.teacherName,Count(e.Grade) As count ,e.studentID ,s.studentName
from EvaluateTeacherGrade e,Course C,Grade G,student s
where e.courseID*=G.courseID and C.courseID*=G.courseID and e.studentID =s.studentID
and e.courseID='200002'and e.studentID='0711001'
GROUP BY C.COURSEID,C.COURSENAME,C.TEACHERID,C.TEACHERNAME ,e.studentID ,s.studentName