Linq group by和order by sum

Question

我只是想用Linq来做这个SQL。但是怎么做呢？

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

我试过了，但失败了:结果只给出了一行。我预计会有比这更多的行。我需要对许多is进行求和计算。

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)应该位于查询的末尾。

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();

否则，您只需查看context.BThread的前10个元素，这些元素似乎具有相同的Id，因此属于同一组。

并且(正如Slai在评论中所说的)删除第二个Id = bTmp.First().Id,。