c# - LINQ GROUP BY 和 MAX()

Question

我正在尝试找出如何在 LINQ 中编写 SQL 语句，但暂时找不到方法，这是 SQL 命令:

SELECT cs.Site_Name, MAX(ed.EffectiveDate_Date)
FROM [WAPMaster].[Factsheets].[EffectiveDate] ed,
[WAPMaster].[Configuration].[Site] cs
WHERE cs.Site_Id = ed.EffectiveDate_SiteId
GROUP BY cs.Site_Name

有人可以帮我了解 linq 语法吗？

**我目前正在尝试这个(感谢 levanlevi)

var test = (from e in this._wapDatabase.EffectiveDates
            join c in this._wapDatabase.Sites 
            on c.Site_Id equals e.EffectiveDate_SiteId
            group e by c.Site_Name into r
            select new
            {
                r.Key.SiteName,
                EffectiveDate = r.Max(d => d.EffectiveDate_Date)
            }); 

但我收到以下错误:

http://i.stack.imgur.com/AkJ5V.png

Answer 1

SELECT  cs.Site_Name ,
        MAX(ed.EffectiveDate_Date)
FROM    [WAPMaster].[Factsheets].[EffectiveDate] ed ,
        [WAPMaster].[Configuration].[Site] cs
WHERE   cs.Site_Id = ed.EffectiveDate_SiteId
GROUP BY cs.Site_Name



from e in WAPMaster.Factsheets.EffectiveDate
join c in WAPMaster.Configuration.Site
on c.Site_Id equals e.EffectiveDate_SiteId
group e by c.Site_Name into r
select new { SiteName = r.Key, EffectiveDate = r.Max(d=>d.EffectiveDate_Date)}