如何在LINQ中的复杂group by上的聚合上使用having子句并在LINQ中加入查询

Question

I have reviewed a lot of the questions and answers here but cant seem to find what I need. I have the following sql below which I am having real trouble getting into a LINQ statement. The specific issue is that for one of the fields I am using a CASE statement both in the select and has part of the HAVING clause. Various reasons why i needed to do this but I cant seem to reproduce it in LINQ.

Here is the sql:

select Count (DetailID) as MonthCount , StoreID, DetailID, SUM(Amount ) as AnnualAmount, PAYear, MIN(CASE when ExportFlag = 'SUCCESS' then 1 when ExportFlag is NULL or  ExportFlag = '' then 0 else - 1 end) as ExpFlag
from Input_Financials
inner join DestinationDetail cdd on cdd .ID = Financials.DetailID
group by StoreID, DetailID, PAYear
Having MIN (CASE when ExportFlag = 'SUCCESS' then 1 when ExportFlag is NULL then 0 else -1 end ) = 0
and Count (*) >= 1
order by PAYear 

This was my best attempt linq statment but you will notice that I dont have the equivalent of the having clause which aggregates the ExportFlag value (which is very important)

   var query =
               from inf in inputActs
               join cgrdets in cgrDetails on inf.DestinationDetailID equals cgrdets.ID
               let export = (inf.ExportFlag == "SUCCESS" ? 2:
                             inf.ExportFlag == "ERROR" ? 1:
                             inf.ExportFlag == null ? 0: 99)
               group inf by new {export, inf.StoreID, inf.DestinationDetailID,inf.PAYr } into g
               where g.Key.export == 0 
               select new { MonthCount = g.Count(), g.Key.StoreID, g.Key.PAYr, Amount = g.Sum(inf=>inf.Amount) };

By the way - please ignore some minor discrepancies you may find in naming of fields between these two - its just probably because i renamed some quickly for the sake of this question.

Answer 1

看起来这就是您想要的：

where g.All(item => item.ExportFlag == "SUCCESS" || item.ExportFlag == null)