mysql - 从具有相同ID的三个表中选择

我有三张桌子

students_first_semester_mark (StudentdID,Subject, Semester_I_Mark )
students_second_semester_mark (StudentdID,Subject, Semester_II_Mark )
students_third_semester_mark (StudentdID,Subject, Semester_III_Mark )

我想要以下输出：

_________________________________________________________________________________
|StudentdID  | Subject |  Semester_I_Mark|  Semester_II_Mark |  Semester_III_Mark
_________________________________________________________________________________

请注意，Semester_I_Mark或Semester_II_Mark可能具有Null值。

我渴望您的回答。

最佳答案

这是你想要的吗？

SELECT [students_first_semester_mark].[StudentdID]
      ,[students_first_semester_mark].[Subject]
      ,[students_first_semester_mark].[Semester_I_Mark]
      ,[students_second_semester_mark].[Semester_II_Mark]
      ,[students_third_semester_mark].[Semester_III_Mark]
FROM [students_first_semester_mark]
JOIN [students_second_semester_mark] ON [students_second_semester_mark].[StudentdID] = [students_first_semester_mark].[StudentdID]
JOIN [students_third_semester_mark] ON [students_third_semester_mark].[StudentdID] = [students_second_semester_mark].[StudentdID]