正确的sql到linq查询

Question

我很难将此sql查询转换为linq查询。我试图通过附加到该订单的订单详细信息选择我的所有订单。在sql中查询是正确的。当我在linq中写它时，一切都变得混乱。这是我的代码：

                var result = from order in orders
                         join orderDetail in orderDetails
                         on order.OrderID equals orderDetail.OrderID

                         select new OrderVm
                         {
                             OrderId = order.OrderID,
                             OrderDetails = order.Order_Details.Select(x =>
                             new OrderDetailVm
                             {
                                 OrderId = orderDetail.OrderID,
                                 UnitPrice = orderDetail.UnitPrice,
                                 Quantity = orderDetail.Quantity,
                                 ProductId = orderDetail.ProductID

                             })
                         };

            return result.ToList();

产生此结果

但是在sql中如果我写

select 
o.OrderID,
o.CustomerID,
od.UnitPrice,
od.Quantity,
od.productid,
p.ProductName   
from Orders o
inner join [Order Details] od
    on o.OrderID = od.OrderID
inner join Products p
    on p.ProductID = od.ProductID
where o.OrderID = 10248

我的预期结果是

Answer 1

从您在嵌套对象中使用Order_Details的方式来看，连接已经存在并且您正在使用的连接是多余的。

 var result = from order in orders
                     select new OrderVm
                     {
                         OrderId = order.OrderID,
                         OrderDetails = order.Order_Details.Select(x =>
                         new OrderDetailVm
                         {
                             OrderId = x.OrderID,
                             UnitPrice = x.UnitPrice,
                             Quantity = x.Quantity,
                             ProductId = x.ProductID
                         })
                     };