c# - LINQ 查询中单个表的多个计数

Question

我在 LINQ 查询中对单个表进行多次计数时遇到问题。我正在使用 NHibernate、LINQ to NHibernate 和 C#。

查询是一个填充列表。我有一个表，它有一个名为 FullRef 的 bool 值。我想做一个 LINQ 查询来计算每个 TrackId 上 FullRef = false 和 FullRef = true 的出现次数。 TrackId 每获取一条track.Source == "UserRef"就得到一个新行。

在下面的查询中，我得到了 FullRef = true 的正确数字计数(来自 FullRefTrueCount)，但它在 FullRefFalseCount 上给出了一个未知的错误数字。

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()
    };

我还尝试修改它，使其不包含分组依据中的 FullRef。这是通过像这样删除 FullRef = track.FullRef 来完成的

var query2 = from track in query
    where track.Source == "UserRef"
    group track by new { TrackId = track.TrackId } 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()
    };

现在它为我提供了 TrackId 的总数，忽略了我的 .Where(x => x.FullRef == true/false) 语句。

有人知道如何修复它吗？我想这是问题所在的“分组依据”。我能以某种方式避免分组吗？我可能需要加入吗？

Answer 1

对于 NHibernate 我不知道，但是使用 Linq With Entity Framework 这应该能得到你想要的:

var query2 = (
    from track in someDbSet
    select new FullReferrer
    {
          Customer = track.trackId
        , FullRefFalseCount = (from fullRefFalse in someDbSet.tracks
                               where fullRefFalse.IsSale == false 
                               && fullRefFalse.trackId == track.trackId
                               select fullRefFalse).Count()
        , FullRefTrueCount = (from fullRefTrue in someDbSet.tracks
                              where fullRefTrue.IsSale == true
                              && fullRefTrue.trackId == track.trackId
                              select fullRefTrue).Count()
    }
).Distinct();