5

我有一张表格，其中汽车的某些部分是分层相关的，而且我还需要在每一行中制造这些零件的成本。这是表格的简化：

parentId  Id description qty manufacturingCost costDescripcion
-------- --- ----------- --- ----------------- ---------------
NULL      1  Car          1  100               Assembly the car
NULL      2  Motorcycle   1  100               Assembly the motrocycle
 1       11  Wheel        4   20               Assembly the wheel
11      111  Rim          1   50               Manufacture the rim
11      112  Tire         1   60               Manufacture the tire
 1       12  Door+Window  4   30               Assembly the door and the window
12      121  Door         1   30               Manufacture the door
12      122  Window       2   10               Manufacture the window
 2       11  Wheel        2   15               Assembly the wheel

我需要从“汽车”开始获取整个家谱，并显示每个分支的总数量和总成本。更好的解释：一辆车有 4 个轮子，每个轮子有 1 个轮辋和 1 个轮胎，所以我应该得到 1 Car, 4 Wheels, 4 Tires, 4 Rims。成本稍微复杂一点：组装汽车的成本为 100 美元，但我必须加上这个成本，即组装 4 个轮子 (4x20) 以及制造 4 个轮辋 (4x50) 和 4 个轮胎的成本（4x60），门窗也是如此。

这是预期的结果：

parentId  Id description qty manufacturingCost   recLevel
-------- --- ----------- --- -----------------   ---------------
NULL       1  Car          1 940 (100+4*130+4*80) 0
 1        11  Wheel        4 130 (20+50+60)       1
 1        12  Door+Window  4 80  (30+30+2*10)     1
12       121  Door         4 30                   2
12       122  Window       8 10                   2
11       111  Rim          4 50                   2
11       112  Tire         4 60                   2

我可以使用递归函数或存储过程轻松实现这一点，但是对于更复杂的结构来说速度非常慢，所以我尝试使用通用表表达式来实现。但我没有找到计算成本的方法。我使用递归 CTE 从顶层开始向下，我得到数量的总和，但我应该从结构的内部到外部来总结成本，我该怎么做？

这是创建表的代码：

CREATE TABLE #Costs 
(
  parentId int, 
  Id int, 
  description varchar(50),
  qty int, 
  manufacturingCost int,
  costDescripcion varchar(150)
)

INSERT INTO #Costs VALUES (NULL , 1, 'Car', 1, 100, 'Assembly the car')
INSERT INTO #Costs VALUES (NULL , 2, 'Motorcycle', 1, 100, 'Assembly the motrocycle')
INSERT INTO #Costs VALUES (1 , 11, 'Wheel', 4, 20, 'Assembly the wheel')
INSERT INTO #Costs VALUES (11 , 111, 'Rim', 1, 50, 'Manufacture the rim')
INSERT INTO #Costs VALUES (11 , 112, 'Tire', 1, 60, 'Manufacture the tire')
INSERT INTO #Costs VALUES (1 , 12, 'Door+Window', 4, 30, 'Assembly the door and the window')
INSERT INTO #Costs VALUES (12 , 121, 'Door', 1, 30, 'Manufacture the door')
INSERT INTO #Costs VALUES (12 , 122, 'Window', 2, 10, 'Manufacture the window')
INSERT INTO #Costs VALUES (2 , 11, 'Wheel', 2, 15, 'Assembly the wheel')

这是我写的 CTE：

with CTE(parentId, id, description, totalQty, manufacturingCost, recLevel)
as
(
  select c.parentId, c.id, c.description, c.qty, c.manufacturingCost, 0
  from #Costs c
  where c.id = 1

  union all

  select c.parentId, c.id, c.description, c.qty * ct.totalQty, c.manufacturingCost, ct.recLevel + 1
  from #Costs c
  inner join CTE ct on ct.id = c.parentId 
)
select * from CTE

这是我得到的结果，正如你所看到的，不是预期的（没有增加成本）：

parentId  Id description qty manufacturingCost recLevel
-------- --- ----------- --- ----------------- ---------------
NULL       1  Car          1 100                0
 1        11  Wheel        4 20                 1
 1        12  Door+Window  4 30                 1
12       121  Door         4 30                 2
12       122  Window       8 10                 2
11       111  Rim          4 50                 2
11       112  Tire         4 60                 2

是否可以使用 CTE 做我想做的事？如果是这样，我该怎么做？

非常感谢，

安团

4

1 回答 1

7

你可以试试这样的

DECLARE @Table TABLE(
        parentId INT,
        Id INT,
        description VARCHAR(50),
        qty FLOAT,
        manufacturingCost FLOAT,
        costDescripcion VARCHAR(50)
)

INSERT INTO @Table SELECT NULL,1,'Car',1,100,'Assembly the car' 
INSERT INTO @Table SELECT NULL,2,'Motorcycle',1,100,'Assembly the motrocycle' 
INSERT INTO @Table SELECT 1,11,'Wheel',4,20,'Assembly the wheel' 
INSERT INTO @Table SELECT 11,111,'Rim',1,50,'Manufacture the rim' 
INSERT INTO @Table SELECT 11,112,'Tire',1,60,'Manufacture the tire' 
INSERT INTO @Table SELECT 1,12,'Door+Window',4,30,'Assembly the door and the window' 
INSERT INTO @Table SELECT 12,121,'Door',1,30,'Manufacture the door' 
INSERT INTO @Table SELECT 12,122,'Window',2,10,'Manufacture the window' 
INSERT INTO @Table SELECT 2,11,'Wheel',2,15,'Assembly the wheel'

;WITH Vals AS (
        SELECT  *,
                qty Level_Qty,
                CAST(id AS VARCHAR(MAX)) + '\' AS [LEVEL]
        FROM    @Table
        WHERE   parentId IS NULL
        UNION ALL
        SELECT  t.*,                
                p.qty * t.qty Level_Qty,
                CAST(p.[LEVEL] AS VARCHAR(MAX))  + CAST(t.id AS VARCHAR(MAX)) + '\' AS [LEVEL]
        FROM    @Table t INNER JOIN
                Vals p  ON  p.Id = t.parentId
)
SELECT  *,
        (SELECT SUM(Level_Qty * manufacturingCost) FROM Vals WHERE [Level] LIKE v.[LEVEL] + '%') / Level_Qty
FROM    Vals v
ORDER BY [LEVEL]

SQL 小提琴示例

于 2012-09-20T11:49:16.077 回答