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) };