Linq to sql 将SQL转换为LINQ

我正在尝试将SQL查询转换为LINQ查询。任何帮助都将不胜感激。 以下是我的SQL查询：

SELECT DISTINCT
 U.UserID,
 U.LoginID,
 U.FirstName,
 U.LastName,
 U.IsActive,
 U.IsApproved,
 U.Email,
 U.DateLastLogin,
 CONVERT(VARCHAR, U.DateLastLogin, 101) AS LastLogin,
 U.JobTitle,
 U.AgencyName,
 U.WorkPhone,
 U.Fax,
 U.MobilePhone,
 U.Satellite,
 U.Blackberry,
 U.Pager,
 U.Address1,
 U.Address2,
 U.City,
 U.StateAbbr,
 U.ZipCode,
 G.[Name] AS GroupName,
 COALESCE( B.UserID, 0 ) AS BTC

 FROM dbo.Users U

 INNER JOIN dbo.Users_Grantee UG ON U.UserID = UG.UserID

 INNER JOIN dbo.Users_Groups UGRP ON UG.UserID = UGRP.UserID
 INNER JOIN dbo.Groups G ON UGRP.GroupID = G.GroupID

 --Flag for BTC Users
 LEFT OUTER JOIN (
      SELECT UG2.UserID
      FROM dbo.Users_Groups UG2
      INNER JOIN dbo.Groups G2 ON UG2.GroupID = G2.GroupID
      WHERE G2.GroupClass_ID = 44
 ) B ON U.UserID = B.UserID

 WHERE U.IsAdminUser = 0
 AND  U.IsActive = @IsActive
 AND  UG.GranteeID = @GranteeID
 AND  G.GroupClass_ID = 1 --Grantee GroupClass
 AND  (U.LastName  LIKE @LastName
  OR   U.FirstName LIKE @FirstName
  OR   U.Email     LIKE @Email
  OR   U.LoginID = @LoginID)


 --Exclude PO users who have grantee access.
 AND NOT EXISTS(
     SELECT 1
     FROM dbo.Users_Groups UG1
     INNER JOIN dbo.Groups G1 ON UG1.GroupID = G1.GroupID
     WHERE UG1.UserID = UG.UserID
     AND  G1.GroupClass_ID <> 1
     AND  G1.GroupClass_ID <> 44
      )

---

不知何故，我通过以下查询实现了这一点：

(from u in Users
     from ugrt in Users_Grantees where (u.UserID == ugrt.UserID)
     from ugrp in Users_Groups where (ugrt.UserID == ugrp.UserID)
     from g in Groups where (ugrp.GroupID == g.GroupID)
    from ug in 
        (from  ug2 in Users_Groups
            join g2 in Groups on ug2.GroupID equals g2.GroupID
                where (g2.GroupClass_ID == 44)
            select new {ug2.UserID}).Where(ug=>ug.UserID == u.UserID).DefaultIfEmpty()
            where   
            u.IsAdminUser == false
            && u.IsActive == true
            && ugrt.GranteeID == 1
            && g.GroupClass_ID == 1
            orderby u.LastName
            select u) 
            .Where (t1 => !(from ugrp1 in Users_Groups 
                join g1 in Groups on ugrp1.GroupID equals g1.GroupID
                where (g1.GroupClass_ID != 1
                    && g1.GroupClass_ID != 44)
                    select new {ugrp1.UserID})
                    .Any(t2 => t2.UserID == t1.UserID))

---

作为LINQ查询，这似乎太长了，为什么需要在LINQ中完成？我建议将其放在一个视图中，但要在LINQ查询中过滤需要参数的部分。可能很难转换，因为不应该这样做？具体来说，JOIN+distinct该视图或存储过程属于数据库。