Better Linq GroupBy

Question

我们正在开发一个广告平台并编写一个负责投放广告的大型查询，向消费者投放广告有几个标准，其中一个标准是广告系列每日预算，所以我们正在做的是我们按单个广告分组以获取展示次数和消耗的成本，然后按广告系列分组，产生以下查询：

  (from a in AdCreative
       join h in AdHit on a.ID equals h.AdID into gh
       join l in AdGroup_Location on a.AdGroupID equals l.AdGroupID into gj
       from subloc in gj.DefaultIfEmpty()
       from subhits in gh.DefaultIfEmpty()
       where a.AdDimensionID == 7 && 
             (subloc == null || subloc.LocationID == 23)
       select new {
           ID = a.ID,
           Name = a.Name,
           Spent = (subhits.AdDimension != null) ? ((double)subhits.AdDimension.Credit / 1000 ) : 0,
           CampaignID = a.AdGroup.Campaign.ID,
           CampaignName = a.AdGroup.Campaign.Name,
           CampaignBudget = a.AdGroup.Campaign.DailyBudget

       })
    .GroupBy(adgroup => adgroup.ID)
    .Select(adgroup => new {
        ID = adgroup.Key,
        Name = adgroup.FirstOrDefault().Name,
        Spent = adgroup.Sum(q =>  q.Spent),
        CampaignID = adgroup.FirstOrDefault().CampaignID,
        CampaignName = adgroup.FirstOrDefault().CampaignName,
        CampaignBudget = adgroup.FirstOrDefault().CampaignBudget,
    })
    .GroupBy(q => q.CampaignID)
    .Select(campaigngroup => new {
      CampaignID = campaigngroup.Key,
      DailyBudget = campaigngroup.FirstOrDefault().CampaignBudget,
      Spent = campaigngroup.Sum(q => q.Spent),
      Ads = campaigngroup.GroupBy(q => q.ID).Select(adgroup => new {
        ID = adgroup.Key,
        Name  = adgroup.FirstOrDefault().Name,
        Spent = adgroup.FirstOrDefault().Spent
    })
    })

正如您在屏幕截图的结果中看到的那样，它运行良好，但是当我检查生成 SQL 查询时，我得到了402 lines of SQL code。怎么可能？我可以做些什么来增强代码

Answer 1

我唯一注意到的是，在最后一个 GroupBy 中，您不聚合，而只显示 Key 和第一个值。我想你也可以在那里Selectq.Id、q.Name和q.Spent。

两个GroupBys 就足够了，因为您显示了两个聚合级别（两次Spent）。