Get sum of two columns in one LINQ query

Question

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

I can do it by two queries:

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

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)};

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

Answer 1

This will do the trick:

LINQ Query Syntax:

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) 
};

LINQ Method Syntax:

m.Items
 .GroupBy(r => 1)
 .Select(g => new 
 {
     SumTotal = g.Sum(x => x.Total), 
     SumDone = g.Sum(x => x.Done) 
 });

Notice that this solution (both syntax) returns a list of 1 item, so you might want to add at the end:

 .FirstOrDefault();