实体到Linq左连接+；分组+；总和

SQL查询（执行计划成本=0.0127553）

C#

结果SQL非常大（执行计划成本=0.0199849）

帮助请编写正确的linq代码。
我的SQL执行计划成本=0.0127553。
Linq SQL执行计划成本=0.0199849。

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21+10记录上的DIFF=00072296。有时您无法发出更好的SQL。但是，您可以编写简单的旧T-SQL并以多种方式调用它：自定义的

DataContext

公开为

IQueryable
的表值UDF就是它们。有时您无法发出更好的SQL。但是，您可以编写简单的旧T-SQL并以多种方式调用它：一个表值的UDF，您定制的
DataContext
可能会将其公开为
IQueryable
，
您只是忘记了这个问题。（哦，我的SQL太胖了）你为什么需要帮助？你的结果有什么问题吗？这些结果是秒数吗？你只是忘记了这个问题。（哦，我的SQL太胖了）你为什么需要帮助？你的结果有问题吗？这些结果是以秒为单位的吗？
SELECT 
 SUM(DATEDIFF(second, DTActivate, DTDeActivate)) AS Seconds,
 AA.ID AS AAID,
 AA.WorkStation
FROM 
 DbLogItems I 
INNER JOIN DbApplicationArguments AA ON 
 AA.Id = I.ApplicationArgument_ID
GROUP BY
 AA.ID,
 AA.WorkStation

var q = from items in db.LogItem

 join aa in db.ApplicationArguments on 
  items.ApplicationArgument.ID equals aa.ID 
 into aaGroup

 from aaJoin in aaGroup.DefaultIfEmpty()

 group items by new 
 {
  aaJoin.ID,
  aaJoin.WorkStation
 } into grouping

 select new 
 {
  Seconds = grouping.Sum(x => SqlFunctions.DateDiff("second", x.DTActivate, x.DTDeActivate)),
  grouping.Key.ID,
  grouping.Key.WorkStation
};

SELECT 
 1 AS [C1], 
 [GroupBy1].[A1] AS [C2], 
 [GroupBy1].[K1] AS [ID], 
 [GroupBy1].[K2] AS [WorkStation] 
FROM 
(
 SELECT 
  [Join1].[K1] AS [K1], 
  [Join1].[K2] AS [K2], 
  SUM([Join1].[A1]) AS [A1] 
  FROM 
  ( 
   SELECT 
    [Extent2].[ID] AS [K1], 
    [Extent2].[WorkStation] AS [K2], 
    DATEDIFF(second, [Extent1].[DTActivate], [Extent1].[DTDeActivate]) AS [A1] 
   FROM 
    [dbo].[DbLogItems] AS [Extent1] 
   LEFT OUTER JOIN [dbo].[DbApplicationArguments] AS [Extent2] 
    ON [Extent1].[ApplicationArgument_ID] = [Extent2].[ID] 
  ) AS [Join1] 
 GROUP BY 
  [K1], 
  [K2] 
) AS [GroupBy1]