c# How to make linq master detail query for 0..n relationship?

Posted by JK on Stack Overflow See other posts from Stack Overflow or by JK
Published on 2010-05-18T03:53:22Z Indexed on 2010/05/18 4:00 UTC
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Given a classic DB structure of Orders has zero or more OrderLines and OrderLine has exactly one Product, how do I write a linq query to express this?

The output would be

OrderNumber - OrderLine - Product Name
Order-1       null        null // (this order has no lines)
Order-2       1           Red widget

I tried this query but is not getting the orders with no lines

var model = (from po in Orders
             from line in po.OrderLines
                select new
                {
                    OrderNumber = po.Id,
                    OrderLine = line.LineNumber,
                    ProductName = line.Product.ProductDescription,
                }
             )

I think that the 2nd from is limiting the query to only those that have OrderLines, but I dont know another way to express it. LINQ is very non-obvious if you ask me!

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