LINQ到SQL多個左聯接使用多個域和子查詢

Question

基本上我希望能夠重新創建此查詢中的LINQ

SELECT * 
FROM Customers 

LEFT JOIN Orders LastOrder 
ON LastOrder.CustomerId = Customers.CustomerId 
&& LastOrder.CreatedOn = (Select MAX(CreatedOn) FROM Orders WHERE CustomerId = Customers.CustomerId) 

LEFT JOIN OrderStatus 
ON OrderStatus.OrderStatusId = LastOrder.OrderStatusId 

Answer 1

這應該是等價的：

from c in dc.Customers 
join o1 in dc.Orders 
on 
new { o1.CustomerId, 
     (from inner 
     in dc.Orders 
     where inner.CustomerId == c.CustomerId 
     select inner.CreatedOn).Max() 
    } 
equals 
new { c.CustomerId, 
     o1.CreatedOn 
    } 
join o2 in dc.Orders 
on 
o1.OrderStatusId == o2.OrderStatusId 
into joined 
select joined