Question

(from pd in context.Report
where pd.ReportDate.Month == 2012
&& pd.ReportDate.Year == 11 && pd.UserID == 11014
group pd by  pd.UserID  into g
select new 
{                               
    Cost = g.Sum(pd => pd.Cost),
    RevenueUSD = g.Sum(pd => pd.Revenue),
});

此查询

 -- Region Parameters
    DECLARE @p0 Int = 2012
    DECLARE @p1 Int = 11
    DECLARE @p2 Int = 11014
    -- EndRegion
    SELECT SUM([t0].[Cost]) AS [Cost], SUM([t0].[Revenue]) AS [RevenueUSD]
    FROM [IntegratedPublisherData] AS [t0]
    WHERE (DATEPART(Month, [t0].[ReportDate]) = @p0) AND (DATEPART(Year, [t0].[ReportDate]) = @p1) AND ([t0].[UserID] = @p2)
    GROUP BY [t0].[UserID]

但我想要

 -- Region Parameters
    DECLARE @p0 Int = 2012
    DECLARE @p1 Int = 11
    DECLARE @p2 Int = 11014
    -- EndRegion
    SELECT SUM([t0].[Cost]) AS [Cost], SUM([t0].[Revenue]) AS [RevenueUSD]
    FROM [IntegratedPublisherData] AS [t0]
    WHERE (DATEPART(Month, [t0].[ReportDate]) = @p0) AND (DATEPART(Year, [t0].[ReportDate]) = @p1) AND ([t0].[UserID] = @p2)

此查询将返回1行，因为UserID被选择为一个值，并且按UserID分组。

如何在没有分组的情况下使用Sum编写此Linq查询？

Answer 1

如果查询返回多行，这也将解决您的问题。也适用于单行。

var query = 
    (from pd in context.Report
     where pd.ReportDate.Month == 11
     && pd.ReportDate.Year == 2012 
     && pd.UserID == 11014
     select pd).ToList() //use .ToList() to avoid doubled execution
var result = 
    new 
    {
        Cost = query.Sum(pd => pd.Cost), 
        RevenueUSD = query.Sum(pd => pd.Revenue) 
    };

Answer 2

删除分组，并从表中读取值。当只有一条记录时，您不需要sum：

from pd in context.Report
where pd.ReportDate.Month == 2012 && pd.ReportDate.Year == 11 && pd.UserID == 11014
select new {                               
   Cost = pd.Cost,
   RevenueUSD = pd.Revenue,
 }

Sum LinqToSql查询没有分组

2 个答案: