LINQ多重计数分组

Question

我在使用NHibernate、LINQ to NHibernate和C#时，无法在单个表格上执行多个计数的LINQ查询。

查询是一个已填充的列表。我有一个包含布尔值FullRef的表格。我想要执行一个LINQ查询，以便计算每个TrackId中FullRef = false和FullRef = true的出现次数。每当TrackId获取track.Source == "UserRef"时，TrackId都会获得一个新行。

在下面的查询中，我可以正确地计算FullRefTrueCount中FullRef = true的数量，但它在FullRefFalseCount中给出了未知的错误数字。

var query2 = from track in query
    where track.Source == "UserRef"
    group track by new { TrackId = track.TrackId, FullRef = track.FullRef } into d

    select new FullReferrer
    {
        Customer = d.Key.TrackId,
        FullRefFalseCount = d.Where(x => x.FullRef == false).Count(),
        FullRefTrueCount = d.Where(x => x.FullRef == true).Count()
    };

有人知道如何解决这个问题吗？我相当确定.Where()子句被忽略了，而" group by"正让我感到困扰。 如果我可以以某种方式

group track by new { TrackId = track.TrackId, FullRefTrue = track.FullRef, FullRefFalse = !track.FullRef }" 

它会起作用。有没有什么办法做到这一点？

- user2464709

Answer 1

如果您想按 trackId 获取结果，只需按 trackId 进行分组即可...

var query2 = query
              .Where(m => m.Source == "UserRef")
              .GroupBy(m => m.TrackId)
              .Select(g => new FullReferrer {
                 Customer = g.Key,
                 FullRefFalseCount = g.Count(x => !x.FullRef),
                 FullRefTrueCount = g.Count(x => x.FullRef)
              });

- Raphaël Althaus