下面的代碼有相同的結果，但無論是在將

但在第二代碼不使用「加入」

請注意，結果是一樣的。

所以我有幾個問題

哪個更好？
哪一個是更快？

CODE01：

(from Member in dContext.TB_FamilyCardMembers 
    select new 
    { 
     Member.FamilyCard_ID, 
     Member.TB_FamilyCard.NoFamilyCard, 
     CardType = Member.TB_FamilyCard.Is_Card == true ? "دفتر عائلة" : "بيان عائلي", 
     FirsN = Member.TB_Person.FirstName, 
     FatherN = Member.TB_Person.FatherName == null ? SelectPersonByID(int.Parse(Member.TB_Person.Father_ID.ToString())).FirstName : Member.TB_Person.FatherName, 
     LastN = Member.TB_Person.LastName == null ? SelectPersonByID(int.Parse(Member.TB_Person.Father_ID.ToString())).LastName : Member.TB_Person.LastName, 
     MotherN = Member.TB_Person.MotherName == null ? SelectPersonByID(int.Parse(Member.TB_Person.Mother_ID.ToString())).FirstName : Member.TB_Person.MotherName, 
     MotherLN = Member.TB_Person.MotherLastName == null ? SelectPersonByID(int.Parse(Member.TB_Person.Mother_ID.ToString())).LastName : Member.TB_Person.MotherLastName 
    }).ToList(); 

______________________________________________

Code02：

(from Member in dContext.TB_FamilyCardMembers 
join Card in dContext.TB_FamilyCards on Member.FamilyCard_ID equals Card.ID 
join Person in dContext.TB_Persons on Member.Person_ID equals Person.ID 
select new 
{ 
    Member.FamilyCard_ID, 
    Card.NoFamilyCard, 
    CardType = Card.Is_Card == true ? "دفتر عائلة" : "بيان عائلي", 
    FirsN = Person.FirstName, 
    FatherN = Person.FatherName == null ? SelectPersonByID(int.Parse(Person.Father_ID.ToString())).FirstName : Person.FatherName, 
    LastN = Person.LastName == null ? SelectPersonByID(int.Parse(Person.Father_ID.ToString())).LastName : Person.LastName, 
    MotherN = Person.MotherName == null ? SelectPersonByID(int.Parse(Person.Mother_ID.ToString())).FirstName : Person.MotherName, 
    MotherLN = Person.MotherLastName == null ? SelectPersonByID(int.Parse(Person.Mother_ID.ToString())).LastName : Person.MotherLastName 
}).ToList();

來源

2016-06-10 Obad Albaali

這是真的http://codereview.stackexchange.com/ – Sudsy

的加入問題需要大量的資源，因此效率較低。 – jdweng