带有连接的SQL查询重复所有其他行的最顶层数据

Question

以下SQL查询检索并重复所有其他行的最顶行的数据。

SELECT 
    Student.StuRollNo, Student.StuName, Student.StuFName, 
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubUrdu' 
       AND M.ExamID = 1) AS Urdu,
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubEng' 
       AND M.ExamID = 1) AS Eng,
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubPhy' 
       AND M.ExamID = 1) AS Phy,
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubChem' 
       AND M.ExamID = 1) AS Chem,
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubBio' 
       AND M.ExamID = 1) AS Bio,
    (SELECT TOP 1 M.SubjectObtMarks 
     FROM Marking M 
     WHERE M.SubjectID = 'SubIsl' 
       AND M.ExamID = 1) AS Isl,
    (SELECT TOP 1 SUM(Marking.SubjectObtMarks) 
     FROM Marking 
     WHERE ExamID = 1) AS ObtMarks
FROM 
    Exam, Student 
INNER JOIN 
    PrimaryData ON Student.StuRollNo = PrimaryData.StuID 
INNER JOIN 
    Section ON Section.SectionID = PrimaryData.SectionID 
WHERE 
    Section.SectionName = 'M1' 
    AND Exam.ExamID = 1;

这是它检索的内容：

数据库图表：

请帮我解决这个问题。谢谢！

Answer 1

这是因为您不限制标记属于哪个学生。 所以你的查询基本上总是拿起第一个标记，而不是检查这个标记属于谁。

SELECT 
Student.StuRollNo, Student.StuName, Student.StuFName, 
(SELECT TOP 1 M.SubjectObtMarks 
 FROM Marking M 
 WHERE M.SubjectID = 'SubUrdu' 
   AND M.ExamID = 1
   AND M.StuID = S.StuID) AS Urdu
FROM 
    Exam, Student S
INNER JOIN 
    PrimaryData ON Student.StuRollNo = PrimaryData.StuID 
INNER JOIN 
    Section ON Section.SectionID = PrimaryData.SectionID