小编Ros*_*han的帖子

我有4张桌子。

CREATE TABLE Branch(
  ID INT,
  Name VARCHAR(50)
);

INSERT INTO Branch VALUES 
(1,'A'), (2,'B');

CREATE TABLE Product(
  ID INT,
  Name VARCHAR(50)
);

INSERT INTO Product VALUES 
(1,'X'), (2,'Y');

CREATE TABLE StockIn(
  ID INT,
  ProductId INT,
  Quantity INT,
  BranchId INT
);

INSERT INTO StockIn VALUES 
(1,1,10,1),
(2,1,20,1),
(3,1,50,2),
(4,1,10,2);

CREATE TABLE StockOut(
  ID INT,
  ProductId INT,
  Quantity INT,
  BranchId INT
);

INSERT INTO StockOut VALUES 
(1,1,5,1),
(2,1,21,1),
(3,1,45,2),
(4,1,5,2);

现在我想根据这些计算库存（StockIn-StockOut）。

通过使用下面的查询，我通过对分支进行分组，从库存表中获取了库存和库存。

库存

select BranchId, ifnull(sum(Quantity),0) Quantity from stockin where productid=1 …

public List<Detail> GetOrderDetails()
{
    var orderDetails = (from user in db.Users
                        join detail in db.OrderDetails
                        on user.Id equals detail.UserId
                        where (detail.DateAdded != null)
                        select new Detail
                        {
                            FirstName = user.FirstName,
                            LastName = user.LastName,
                            Origin = detail.OriginCode,
                            Destination = detail.DestinationCode,
                            CarrierCode = detail.CarrierCode,
                            IsReturn = detail.IsReturn,
                            IsCancel = detail.IsCancel,
                            OrderId = detail.OrderId
                        }).FirstOrDefault();
    return Json(orderDetails);
}

此代码给出了以下错误.

无法隐式转换类型' System.Web.Mvc.JsonResult'到'System.Collections.Generic.List<TravelingAdmin.Controllers.Detail>