Simple sql to Linq query with group by and aggregate functions

Question

I\'m fighting with linq trying to learn the syntax and I can\'t figure out how to do the following simple query

SELECT DISTINCT
    user.firstname,
    user.last         


        

Answer 1

I think you have a discrepancy in your join clause -- you're inner joining invoice to itself on user_id. I assume that you intended to join this to user?

In any case, here's my best shot:

from inv in invoices
group inv by new { inv.user_id } into userInv
join usr in users on userInv.Key.user_id equals usr.user_id
where usr.company_user.company_id = 1
select new
{
    usr.firstname,
    usr.lastname,
    amount = inv.Count(),
    sum = inv.Sum(amt => amt.amount)
}

As for LINQ suggestions, I'd definitely suggest you download and play around with LINQPad. I use it all the time to test LINQ statements without Visual Studio. It'll convert your LINQ statements to SQL as well, which is probably of particular interest to you.

Edit: Enigmativity's statement is a lot closer to what you requested than mine is. I hadn't stumbled onto the column grouping in the examples I worked with.