访问查询查找所有链接匹配的所有记录

Question

表格：

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

我想返回所有学科得分都超过（例如70分）的不同学生。 选择[学生姓名]

学生可以注册1个或多个科目。 如果学生甚至有一门学科没有达到要求的分数，则不应列出他们。

从他上面的数据我希望看到

Mark
Fred

SQL查询将对此做什么？

Answer 1

如果NULL值对您不利，那么

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