linq分組和計數

Question

select  uc.adminid, count(*)
from Users uc
join UsersMessage ucm on uc.admincallid = ucm.admincallid
where uc.CallDate between '2016-08-01' and '2016-09-01' and ucm.type = 4
group by uc.adminid
order by count(*)

這是我嘗試過的：

 public static Dictionary<int, int> ReturnSomething(int month)
        {

            Dictionary<int, int> dict = new Dictionary<int, int>();
            using (DataAccessAdapter adapter = new DataAccessAdapter())
            {
                LinqMetaData meta = new LinqMetaData(adapter);
                dict = (from uc in meta.Users
                        join ucm in meta.meta.UsersMessage on uc.AdminCallId equals ucm.AdminCallId 
                        where ucm.type == 4 && uc.CallDate.Month == month
                        group uc by uc.AdminId into g
                        select new { /* ???? adminid = g. */ }).ToDictionary(x => new Dictionary<int, int>(/* ????? x, x.Name*/));
            }

            return dict;
        }

我怎樣才能達到我所需要的？

Answer 1

字典的鍵是GroupBy的鍵，值是Count() ，因此您需要：

// ...
.ToDictionary(g => g.Key, g => g.Count()); // key is AdminCallId and value how often this Id occured

既然您已經問過如何以降序排列：

您正在建立沒有順序的字典（嗯，它應該讀為：它是不確定的）。 因此，訂購完全沒有必要。 為什么它是無序的？ 讀這個

但是，如果您要創建其他東西，並且想知道如何通過Count DESC訂購，則可以使用以下命令：

from uc in meta.Users
join ucm in meta.meta.UsersMessage on uc.AdminCallId equals ucm.AdminCallId 
where ucm.type == 4 && uc.CallDate.Month == month
group uc by uc.AdminId into g
orderby g.Count() descending
select new { adminid = g.Key, count = g.Count() })