爲什麼我的SQL結果不符合我的Linq結果？

Question

當我在SQL運行此查詢我得到我想要的東西：

SELECT Auckland_Park.Formative.[Formative Name] 
FROM Auckland_Park.LearningUnit 
INNER JOIN Auckland_Park.Formative 
ON Auckland_Park.LearningUnit.ID = Auckland_Park.Formative.FK_LU 
INNER JOIN Auckland_Park.Reference 
INNER JOIN Auckland_Park.Course 
ON Auckland_Park.Reference.FK_Course = Auckland_Park.Course.ID 
ON Auckland_Park.LearningUnit.ID = Auckland_Park.Reference.FK_LU 
WHERE Auckland_Park.Course.Name = 'BI' 

我的結果：

Querying SQL Build 
Report Develop 
Java App Develop 
Andriod App Set up 
SharePoint Server 

但是，當我與我使用LINQ到SQL我的C＃應用​​程序，我的LINQ工作查詢看起來是這樣的：

//LINQ Query to fill Foramtive Name ComboBox 
CTUDataContext data = new CTUDataContext(); 
var course = (from r in data.LearningUnits      
       join a in data.Formatives 
       on r.ID equals a.FK_LU 
       join f in data.References 
       on r.ID equals f.FK_LU 
       join g in data.Courses 
       on f.FK_LU equals g.ID 
       where g.Name == ("BI") 
       select new 
       { 
        formativeName = a.Formative_Name, 
        ID = a.ID 

       } 
      ).ToList(); 
txtFormativeName.ItemsSource = course; 
txtFormativeName.DisplayMemberPath = "formativeName"; 
txtFormativeName.SelectedValuePath = "ID"; 

這似乎是相同的，但我沒有變，我會繼續使用SQL查詢以上得到相同的結果。

Answer 1

//LINQ Query to fill Foramtive Name ComboBox 
CTUDataContext data = new CTUDataContext(); 
var course = (from r in data.LearningUnits      
       join a in data.Formatives 
       on r.ID equals a.FK_LU 
       join f in data.References 
       on r.ID equals f.FK_LU 
       join g in data.Courses 
       on f.FK_LU equals g.ID 
       where g.Name == ("BI") 
       select new 
       { 
        formativeName = a.Formative_Name, 
        ID = a.ID 

       } 
      ).ToList(); 
txtFormativeName.ItemsSource = course; 
txtFormativeName.DisplayMemberPath = "formativeName"; 
txtFormativeName.SelectedValuePath = "ID"; 

答：

on f.FK_LU equals g.ID 


f.FK_LU 

必須

f.FK_Course