SQL Server 實現單列累積乘

--PRODUCT 即乘積
IF OBJECT_ID('dbo.RecursiveMultiplication') IS NOT NULL DROP TABLE dbo.RecursiveMultiplication;
CREATE TABLE RecursiveMultiplication
(Id INT, Num DECIMAL(9,2));
INSERT INTO RecursiveMultiplication VALUES
(3321,4),
(3332,2),
(3357,3),
(3358,9),
(3361,12),
(3378,7);
SELECT * FROM RecursiveMultiplication;

WITH TEMP AS (
SELECT RN=ROW_NUMBER() OVER(ORDER BY (SELECT NULL))
--此處先爲原表實現默認排序
     , rm.Id
     , rm.Num
  FROM RecursiveMultiplication rm
), Rmt AS (
SELECT t.RN
     , t.Id
     , t.Num
     , CONVERT(DECIMAL(9,2),t.Num) PRODUCT
  FROM TEMP t
 WHERE t.RN=1
UNION ALL
SELECT t.RN
     , t.Id
     , t.Num
	 , CONVERT(DECIMAL(9,2),t.Num*r.PRODUCT) PRODUCT
  FROM Rmt r
       INNER JOIN TEMP t ON r.RN=t.RN-1
)
SELECT r.Id
     , r.Num
	 , r.PRODUCT
  FROM Rmt r
ORDER BY r.RN