在一个 LINQ 查询中获取两列的总和

Get sum of two columns in one LINQ query(在一个 LINQ 查询中获取两列的总和)

问题描述

假设我有一张名为项目 (ID int, Done int, Total int)

let's say that I have a table called Items (ID int, Done int, Total int)

我可以通过两个查询来完成:

I can do it by two queries:

int total = m.Items.Sum(p=>p.Total)
int done = m.Items.Sum(p=>p.Done)

但我想在一个查询中完成，如下所示:

But I'd like to do it in one query, something like this:

var x = from p in m.Items select new { Sum(p.Total), Sum(p.Done)};

当然有一种方法可以从 LINQ 语法调用聚合函数......?

Surely there is a way to call aggregate functions from LINQ syntax...?

推荐答案

这样做可以解决问题:

from p in m.Items
group p by 1 into g
select new
{
    SumTotal = g.Sum(x => x.Total), 
    SumDone = g.Sum(x => x.Done) 
};

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