Question

I need to write following query in Linq to SQL but not sure what is the best way of doing, given it has two derived tables. Any suggestions.

SELECT A.ID  
FROM  
(   
    SELECT *   
    FROM Orders   
    WHERE ProductID = 5  
) A  
JOIN  
(  
    SELECT CustomerID, MAX(Price) Price   
    FROM Orders   
    WHERE ProductID = 5  
    GROUP BY CustomerID  
) B  
ON A.CustomerID = B.CustomerID and A.Price = B.Price  

Answer 1

var b = (
    from o in db.Orders
    where o.ProductID == 5
    group o by o.CustomerID into og 
    select new {
        CustomerID = og.Key
        Price = Max(og.Price)
    }
);
var a = (
    from o in db.Orders
    join p in b on new {a.CustomerID, a.Price} equals 
            new {b.CustomerID, b.Price}
    where o.ProductID == 5
    select a.ID
);
var r = a.ToString();

These two links are invaluable when forming things like this:

• http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
• http://msdn.microsoft.com/en-us/vstudio/bb688085