LINQ GROUP BY和MAX（）

Question

你好，我试图找出如何写在LINQ的SQL语句，但我无法找到一个方法来做到这一点的时刻，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 

请问有人可以帮我理解linq语法吗？由于

**我想这个到目前为止（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) 
      }); 

但我发现了以下错误：

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)} 

Answer 2

var test = (from effectiveDates in this._wapDatabase.EffectiveDates       
      from sites in this._wapDatabase.Sites       
      where sites.Site_Id = effectiveDates.EffectiveDate_SiteId 
        group effectiveDates by sites.Site_Id into g       
      select new { siteId = g.key , effectiveDate = g.max(ed => ed.EffectiveDate_Date)});