Help with adding in LINQ to SQL query

I have an html table that is displaying customer orders. One of these columns is a sub total which needs to add all rows for sub total in the order details table for that specific order. Is there a way to do this within my anonymous type?

Here's some images of what I'm talking about:

And the code i'm using minus the total amount addition:

var q = db.Orders.Where(x => x.siteUserID == 41)
                      .OrderByDescending(x => x.orderID)
                      .Select(x => new
            {
                dateCreated = x.dateCreated,
                orderID = x.orderID,
                count = x.OrderDetails.Count()
            });

Currently I've created a class wit开发者_高级运维h identical properties of my LINQ query, and am adding the results to a List and within the list calling a function that adds up the sub total.

If it could be done within my original query it would be much cleaner.

I was looking for Sum

subtotal = x.OrderDetails.Sum(t=> t.subTotal)