百分比细分

Question

我想知道是否有人可以帮助我解决这个产品百分比细分挑战。

我有以下代码将数据插入 table。

DROP TABLE IF EXISTS #ProductBreakdown
CREATE TABLE #ProductBreakdown
(
  Product VARCHAR(20)
  , [TotalSales] decimal(20, 2)
  , Percentage decimal(20, 2)
)
;

INSERT INTO #ProductBreakdown VALUES('Product A', 596.42, 0)
INSERT INTO #ProductBreakdown VALUES('Product A', 127.55, 0)
INSERT INTO #ProductBreakdown VALUES('Product A', 736.83, 0)
INSERT INTO #ProductBreakdown VALUES('Product B', 379.51, 0)
INSERT INTO #ProductBreakdown VALUES('Product B', 205.95, 0)
INSERT INTO #ProductBreakdown VALUES('Product C', 905.99, 0)

本SELECT查询returns正确的百分比结果，即

SELECT PB.Product, PB.TotalSales, 
  [TotalSales] / SUM([TotalSales]) OVER(PARTITION BY Product) * 100 AS PercentageSales
FROM #ProductBreakdown PB

Product	TotalSales	PercentageSales
Product A	596.42	40.83
Product A	127.55	8.73
Product A	736.83	50.44
Product B	379.51	64.82
Product B	205.95	35.18
Product C	905.99	100.00

我现在想使用 UPDATE 语句将这些百分比提交到 table 中。我正在使用以下语句

UPDATE #ProductBreakdown SET [Percentage] =
(SELECT 
  [TotalSales] / SUM([TotalSales]) OVER(PARTITION BY Product) * 100 AS PercentageSales
FROM #ProductBreakdown PB2 WHERE PB1.Product = PB2.Product AND PB1.TotalSales = PB2.TotalSales)
FROM #ProductBreakdown PB1

SELECT * FROM #ProductBreakdown

但是，这 returns 每行 100%。

有没有人对what/where我出错有什么建议？

Answer 1

您可以将您的计算包含在 CTE 中并简单地更新它：

with updateme as (
    select *,
      TotalSales / Sum(TotalSales) over(partition by Product) * 100 as PercentageSales
    from #ProductBreakdown 
)
update updateme set Percentage = PercentageSales;

Answer 2

您犯的错误是您还关联了子查询中的 TotalSales 列，而不仅仅是 Product.

但是您可以更新 CTE 或派生 table 而无需连接或重新扫描基础 table

UPDATE pb
SET Percentage = pb.PercentageSales
FROM (
    SELECT *,
      pb.TotalSales / SUM(pb.TotalSales) OVER (PARTITION BY pb.Product) * 100 AS PercentageSales
    FROM #ProductBreakdown pb
) pb;

但我还是建议您为此使用视图，否则您将不得不使其与触发器保持同步。

百分比细分

Percentage breakdown

sql

tsql

sql-server

percentage

sql-server-2016