LINQ的GROUP BY和總和

Question

爲了我只是想這樣做，SQL Linq中。但是如何？

Select Id, sum(Count) 
from dbo.BThread 
group by Id 
order by sum(Count) desc 

我試過了，失敗了：結果只給出了一行。我希望有更多的行比這更多。我需要總結許多ID。

var List = (from tbBThread in context.BThread.Take(10) 
       group tbBThread by tbBThread.Id into bTmp 
       orderby bTmp.Sum(x => x.Count) 
       select new BViewModel 
       { 
        Id = bTmp.Key, 
        Id = bTmp.First().Id, 
        Count = bTmp.Sum(x => x.Count) 
       }).ToList(); 

Answer 1

Take(10)應該在你的查詢結束。

var List = (from tbBThread in context.BThread 
      group tbBThread by tbBThread.Id into bTmp 
      orderby bTmp.Sum(x => x.Count) 
      select new BViewModel 
      { 
       Id = bTmp.Key, 
       Count = bTmp.Sum(x => x.Count) 
      }).Take(10).ToList(); 

否則，你只能看你的context.BThread的前10個元素，這似乎有相同的Id，從而進入了同一組。

及（如SLAI在評論中已經說過了）刪除第二個Id = bTmp.First().Id,。