linq分组和计数

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(*)

这是我尝试过的：

 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;
        }

我怎样才能达到我所需要的？

Answer 1

字典的键是GroupBy的键，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

既然您已经问过如何以降序排列：

您正在建立没有顺序的字典（嗯，它应该读为：它是不确定的）。 因此，订购完全没有必要。 为什么它是无序的？ 读这个

但是，如果您要创建其他东西，并且想知道如何通过Count DESC订购，则可以使用以下命令：

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() })