LINQ到SQL GROUP BY和总和选择 [英] Linq to SQL Group by and Sum in Select

问题描述

我需要转换的SQL查询到LINQ的：

I need to convert that SQL Query into Linq:

SELECT
    SUM([ArticleAmount]) as amount
    ,[ArticleName]
FROM [DB].[dbo].[OrderedArticle]

group by articlename

order by amount desc

我尝试以下code，但我在a.ArticleName，上面写着ArticleName的定义，得到一个错误就会丢失。

I tried the following code but I get an error at "a.ArticleName" that says a definition of "ArticleName" would be missing.

var sells = orderedArt
            .GroupBy(a => a.ArticleName)
            .Select(a => new {Amount = a.Sum(b => b.ArticleAmount),Name=a.ArticleName})
            .OrderByDescending(a=>a.Amount)
            .ToList();

现拥有你这样的人，并知道如何解决这个问题？

Has someone of you and idea how to fix this?

感谢您的帮助！

推荐答案

您收到此错误，因为分组不返回的IEnumerable＆LT; OrderedArticle＆GT; ，但的IEnumerable＆LT; IGrouping＆LT;字符串，OrderedArticle＆GT;＆GT;

You are getting this error because the Grouping doesn't return IEnumerable<OrderedArticle> but IEnumerable<IGrouping<string, OrderedArticle>>

您需要更改code使用 a.Key ：

You need to change your code to use a.Key:

var sells = orderedArt
    .GroupBy(a => a.ArticleName)
    .Select(a => new { Amount = a.Sum(b => b.ArticleAmount), Name = a.Key})
    .OrderByDescending(a => a.Amount)
    .ToList();

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