Question

I m 试图将以下内容转换为LINQ。我先天成功,有1个小组,但无法工作。希望得到任何帮助。

  select ContactID, EventID, Count=count(*) 
  from ScanLogs s, Exhibits e
  where s.ExhibitID = e.ExhibitID
  group by s.ContactID, e.EventID

结果是:

ContactID EventID Count
300009 2000048 2
300009 2000096 1
300036 2000096 1

Answer 1

我认为,这样做是:

var query = from s in ScanLogs
            from e in Exhibits
            where s.ExhibitID == e.ExhibitID
            group 1 by new { s.ContactID, e.EventID } into g
            select new { g.Key.ContactID, g.Key.EventID, Count = g.Count() };

在此情形下,你只是重新计算了多少。

不过,我可能已经使用过一起。这应当等同。

var query = from s in ScanLogs
            join e in Exhibits on s.ExhibitID equals e.ExhibitID
            group 1 by new { s.ContactID, e.EventID } into g
            select new { g.Key.ContactID, g.Key.EventID, Count = g.Count() };

Answer 2

另一支使用加入和组合的arian。

var query = from c in ScanLogs
            join d in Exhibits on c.ExhibitID equals d.ExhibitID
            group new{
             g.Key.ContactID,
             g.Key.EventID,
             Count = g.Count()
            }
            by new {
              c.ContacID, d.EventID
            } into g
            select g;

友情链接