访问查询查找所有链接匹配的所有记录

Question

Tables:

tblStudents:
ID, Student Name
1, John
2, Mark
3, Fred

tblEnrolledSubjects:
ID, Student ID, Subject ID, Score
1, 1, 1, 75
2, 1, 2, 75
3, 1, 3, 75
4, 1, 4, NULL
5, 2, 1, 75
6, 3, 1, 75
7, 3, 2, 80
8, 3, 3, 85

tblSubject:
ID, Subject Name
1, Maths
2, English
3, Science
4, History

I want to return all distinct students that have a score of over (say 70) for all subjects. SELECT [Student Name]

Students can be enrolled in 1 or more subjects. If a student has even one subject not of required score then they should not be listed.

From he above data I would expect to see

Mark
Fred

What would the SQL query be for this?

Answer 1

If a NULL value doesn't count against you, then

SELECT tblStudents.[Student Name]
FROM tblEnrolledSubjects RIGHT JOIN tblStudents 
    ON tblEnrolledSubjects.[Subject ID] = tblStudents.ID
GROUP BY tblStudents.[Student Name]
HAVING (Min(tblEnrolledSubjects.[Score])>=70);

Answer 2

SELECT t.Studentname
  FROM tblStudents t JOIN
      (select count(*) cnt, min(nz(score,0)) minscore, StudentID
         FROM tblEnrolledSubjects
     GROUP BY StudentID) s
   ON t.Studentid = s.studentid
WHERE minscore>=70 --if mark is greater than or equal to 70