Sql 如何用AVCO永续法计算仓库成本

如果您对AVCO永续法一无所知，只需阅读或在回答问题之前：

为了更清楚，我将我的数据放在我的事务表中：

数量列包含已购买或出售的商品金额（负数表示销售发票）

我需要在SQL Server中编写一个查询，返回如下记录集：

成本列包含根据AVCO永续法计算的交易时的产品成本

以下是生成表和数据所需的查询：

CREATE TABLE [dbo].[Transactions]
    (
      [Id] [INT] NOT NULL ,
      [Date] [DATE] NOT NULL ,
      [Coefficient] [INT] NOT NULL ,
      [Quantity] [INT] NOT NULL ,
      [Price] [INT] NOT NULL ,
      [Cost] [REAL] NOT NULL ,
      CONSTRAINT [PK_Transactions] PRIMARY KEY CLUSTERED ( [Id] ASC )
        WITH ( PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF,
               IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
               ALLOW_PAGE_LOCKS = ON ) ON [PRIMARY]
    )
ON  [PRIMARY]

GO
INSERT  [dbo].[Transactions]
        ( [Id], [Date], [Coefficient], [Quantity], [Price], [Cost] )
VALUES  ( 1, '2017-01-01', 1, 10, 100, 100 ),
        ( 2, '2017-01-02', 1, 20, 120, 113.33 ),
        ( 3, '2017-01-03', -1, 5, 200, 113.33 ),
        ( 4, '2017-01-04', 1, 10, 150, 123.8 ),
        ( 5, '2017-01-05', -1, 3, 200, 123.8 ),
        ( 6, '2017-01-06', -1, 10, 200, 123.8 ),
        ( 7, '2017-01-07', 1, 10, 180, 141.36 ),
        ( 8, '2017-01-07', -1, 5, 220, 141.36 )

更新

我只是想简单了解一下我是如何计算成本域的：

((PreviousCost*PreviousStock)+(CurrentPrice*CurrentQuantity))/CurrentStock

---

以下查询将满足您的需要

CREATE TABLE #Temp
(
 Date1      DATE,
 AvgCost        decimal(18,4)
 )

 DECLARE @QTY       FLOAT,
         @QTY1      FLOAT,
         @Price     FLOAT,
         @Date      DateTime,
         @Cost      FLOAT, 
         @Cost1     FLOAT,
         @RoundCost FLOAT


SELECT @Cost = 0, @QTY = 0, @RoundCost=0
DECLARE Cur_ CURSOR FOR
 SELECT [Date], [Coefficient]*[Quantity], [Price],  ([Quantity] * [Price])  
FROM [dbo].[Transactions]
ORDER BY [Date] ASC, [Coefficient] DESC

OPEN Cur_
FETCH NEXT FROM Cur_ INTO @Date, @QTY, @Price, @Cost
WHILE @@FETCH_STATUS = 0
BEGIN
    IF(@QTY > 0)
    BEGIN
    SELECT @Cost = @Cost + @RoundCost
    END
    ELSE
    BEGIN
    SELECT @Cost = (@Cost1 * (@QTY+@QTY1))
    END

    SELECT @QTY = @QTY + ISNULL(SUM([Coefficient]*[Quantity]),0)  FROM [dbo].[Transactions]
    WHERE  [Date] < @Date

    --SELECT  @Date, @QTY, @Price,  @Cost,  @Cost / @QTY
    INSERT INTO #Temp
    SELECT  @Date, @Cost / @QTY
    SET @Cost1 = @Cost / @QTY
    SET @QTY1 =  @QTY
    SET @RoundCost = @Cost
    FETCH NEXT FROM Cur_ INTO @Date, @QTY, @Price, @Cost
END 

CLOSE Cur_
DEALLOCATE Cur_

SELECT * FROM #Temp T
DROP TABLE #Temp

---

如果货物售出，如何计算成本。我得出的答案是没有销售发票记录就意味着没有采购记录@Saeed Hamed。@ SyaMvima我必须考虑出售的项目，因为对股票的影响。我做了一个更新并简要解释了如何计算成本。我希望下面的答案能达到最大值…谢谢你的回答，但是这种方法太慢了，我需要一个可以用作视图对象的查询。我已经提出了使用CTE的递归表，但这也是相当缓慢的。

(1 row(s) affected)
Date1      AvgCost
---------- ---------------------------------------
2017-01-01 100.0000
2017-01-02 113.3333
2017-01-03 113.3333
2017-01-04 123.8095
2017-01-05 123.8095
2017-01-06 123.8095
2017-01-07 141.3690
2017-01-07 224.5273

(8 row(s) affected)