SQL外连接在LINQ

Question

我有以下LINQ查询

from s in db.tblSave 
join a in db.tblAssessment on s.AssessmentID equals a.Id 
join staff in db.tblStaff on s.StaffID equals staff.Id 
join student in db.tblStudent on s.StudentID equals student.Id 
join signed in db.tblSaveSigned on s.Id equals signed.SaveID 
select new 
{ 
SaveID = s.Id, 
StaffName = staff.StaffName, 
AssessmentName = a.AssessmentName, 
StudentName= student.StudentName, 
CreatedDate = s.CreatedDate, 
SignedDate = signed.SignedDate} 

tblSaveSigned可能没有对tblSave记录，是除一些tblSave记录。我如何在结果中包含所有tblSave记录？这是SQL中的外连接，但不知道如何在LINQ中完成。

在此先感谢。

是否有LINQ工具的SQL？

Answer 1

以下是在tblSave for tblSaveSigned上放置FULL OUTER JOIN的正确LINQ查询。感谢NetMage为我指出了正确的方向。

from s in db.tblSave 
join a in db.tblAssessment on s.AssessmentID equals a.Id 
join staff in db.tblStaff on s.StaffID equals staff.Id 
join student in db.tblStudent on s.StudentID equals student.Id 
join signed in db.tblSaveSigned on s.Id equals signed.SaveID into signedj 
from signed in signedj.DefaultIfEmpty() 
select new 
{ 
SaveID = s.Id, 
StaffName = staff.StaffName, 
AssessmentName = a.AssessmentName, 
StudentName= student.StudentName, 
CreatedDate = s.CreatedDate, 
SignedDate = signed.SignedDate}