Nested Left Outer Inner Join Example in C# LINQ

public List<Customer> CustomerList; 
StringBuilder sbResult = new StringBuilder();
// Define default order instance
Order emptyOrder = new Order { OrderID = 0, CustomerID = "XXXXX", EmployeeID = 0,
                               OrderDate = DateTime.Parse("1/1/1900"),
                               RequiredDate = DateTime.Parse("1/1/1900"), 
                               ShipVia = 0, 
                               Freight = 0M, 
                               ShipName = "Default Order" };
 
var query11 = from c in CustomerList
              where c.Country == "USA"
              join o in OrderList 
                  on c.CustomerID equals o.CustomerID into co
              from d in co.DefaultIfEmpty(emptyOrder)
              select new { c, d };
 
foreach (var c in query11)
        sbResult.Append(String.Format("CustID = {0}, Name = {1}, OrderID = {2}, OrderDate = {3:d}\r\n",
           c.c.CustomerID, c.c.CompanyName, c.d.OrderID, c.d.OrderDate));