如何使用lambda表达式连接2个表

Question

任何人都可以告诉我如何使用lambda表达式来编写这个sql查询。

我想加入CoachingLang.ExpandedForm & CoachingLang.ExpandedCategory CoachingDef.FormCategory。

SELECT Ef.Translation +' - '+ Ec.Translation, Fc.FormCategoryID, Ef.FormId,Ef.Translation, Ec.CategoryId, Ec.Translation 
FROM CoachingDef.FormCategory Fc 
INNER JOIN CoachingLang.ExpandedForm Ef ON Fc.FormID = Ef.FormId 
AND Ef.DictionaryId = -2147483645 AND Ef.PropertyId = -2147483647 
INNER JOIN CoachingLang.ExpandedCategory Ec ON Fc.CategoryID = Ec.CategoryId 
AND Ec.DictionaryId = -2147483645 AND Ec.PropertyId = -2147483647 

Answer 1

from Fc in CoachingDef.FormCategory 
join Ef in CoachingLang.ExpandedForm on Fc.FormID equals Ef.FormId 
join Ec in CoachingLang.ExpandedCategory on Fc.CategoryID equals Ec.CategoryId 
where Ef.DictionaryId = -2147483645 && Ef.PropertyId = -2147483647 
&& Ec.DictionaryId = -2147483645 && Ec.PropertyId = -2147483647 

select new {Translation = Ef.Translation +' - '+ Ec.Translation, 
    Fc.FormCategoryID, Ef.FormId,Ef.Translation, 
    Ec.CategoryId, Ec.Translation} 

Answer 2

加盟是LAMBDA形式杂乱，但这里有云：

CoachingDef.FormCategory 
      .Join(CoachingLang.ExpandedForm, 
        Fc => new {Fc.FormID, 
          DictionaryId = -2147483645, 
          PropertyId = -2147483647} // primary key 
        Ef => new {Ef.FormId, 
          Ef.DictionaryId, 
          Ef.PropertyId} // foreign key 
        (Fc,Ef) => new {Fc, Ef}) 
      .Join(CoachingLang.ExpandedCategory, // the "left" side is now the merged Fc/Ef type 
        FcEf => new {FeEf.Fc.CategoryID, 
           DictionaryId = -2147483645, 
           PropertyId = -2147483647} // primary key 
        Ec => new {Ec.CategoryId, 
          Ec.DictionaryId, 
          Ec.PropertyId} // foreign key 
        (FcEf,Ec) => new {FcEf.Fc, FcEf.Ef, Ec}) 
      .Select(FcEfEc => new {Translation = FcEfEc.Ef.Translation +' - '+ FcEfEc.Ec.Translation, 
            FcEfEc.Fc.FormCategoryID, 
            FcEfEc.Ef.FormId, 
            FcEfEc.Ef.Translation, 
            Ec.CategoryId, 
            Ec.Translation 
            }) 

这是一个在查询语法干净了一点：

from Fc in CoachingDef.FormCategory 
join Ef in CoachingLang.ExpandedForm on 
    new {Fc.FormID, 
     DictionaryId = -2147483645, 
     PropertyId = -2147483647} 
    equals new { Ef.FormId, 
     Ef.DictionaryId, 
     Ef.PropertyId} 
join Ec in CoachingLang.ExpandedCategory on 
    new {Fc.CategoryID, 
     DictionaryId = -2147483645, 
     PropertyId = -2147483647} 
    equals new Ec.CategoryId, 
     Ec.DictionaryId, 
     Ec.PropertyId} 
select new {Translation = Ef.Translation +' - '+ Ec.Translation, 
      Fc.FormCategoryID, 
      Ef.FormId, 
      Ef.Translation, 
      Ec.CategoryId, 
      Ec.Translation}