我可以将 PARTITION BY 与 GROUP BY 子句一起使用吗？ SQL 服务器 2012

Question

我是窗口函数的新手。这是原始的 table 有 4 种水果。

fruit   quantity
orange  100
banana  27
banana  20
orange  5
melon   5
apple   1
banana  10
banana  4
banana  36
banana  86
banana  47
apple   32
banana  7
banana  5
banana  3

是否可以将其转换为每种水果占所有水果总量的百分比？这是我想要的：

fruit       total       percentage
apple       33          9%
banana      245         63%
orange      105         27%
melon       5           1%

这是我正在尝试的代码，但它给我一个错误：

SELECT fruit
, SUM(quantity) / SUM(quantity) OVER () * 100
FROM fruit_inventory
GROUP BY fruit

如果我撤消 GROUP BY 并删除第一个 SUM(quantity)，那么我会得到多个如下所示的记录：

fruit   quantity    percentage
apple   1           0%
apple   32          8%
banana  27          7%
banana  20          5%
banana  10          3%
banana  4           1%
banana  36          9%
banana  86          22%
banana  47          12%
banana  7           2%
banana  5           1%
banana  3           1%
melon   5           1%
orange  100         26%
orange  5           1%

Answer 1

我相信这就是您要找的：

declare @fruitbasket table
    (
     Fruit nvarchar(50),
     Quantity decimal(19, 5)
    );

insert  into @fruitbasket
        (Fruit, Quantity)
values  (N'orange', 100),
        (N'banana', 27),
        (N'banana', 20),
        (N'orange', 5),
        (N'melon', 5),
        (N'apple', 1),
        (N'banana', 10),
        (N'banana', 4),
        (N'banana', 36),
        (N'banana', 86),
        (N'banana', 47),
        (N'apple', 32),
        (N'banana', 7),
        (N'banana', 5),
        (N'banana', 3);

select  Fruit,
        sum(Quantity) as Quantity,
        sum(Quantity) / (
                         select sum(Quantity) as Total
                         from   @fruitbasket
                        ) * 100 as PercentageOfTotal
from    @fruitbasket
group by Fruit;

Answer 2

使用聚合 sum 的窗口 sum。

SELECT  Fruit ,
        SUM(Quantity) AS Quantity ,
        SUM(Quantity) / SUM(SUM(Quantity)) OVER () * 100
FROM    @fruitbasket
GROUP BY Fruit;

Answer 3

使用 CTE（通用 Table 表达式）您可以获得想要的结果。总体而言，CTE 确实具有更好的性能和更好的可读性。

WITH cte AS
(
    SELECT DISTINCT 
        Fruit
        ,SUM(Quantity) OVER (PARTITION BY fruit ORDER BY fruit) AS sumProducts
        ,SUM(SUM(Quantity)) OVER ()  AS totalProducts
    FROM Whosebug
    GROUP BY 
        Fruit
        ,Quantity
)
SELECT Fruit, CAST(sumProducts AS INT) AS sumProducts, CAST(100 * sumProducts / totalProducts AS DECIMAL(5,2)) AS percentage
FROM cte

我可以将 PARTITION BY 与 GROUP BY 子句一起使用吗？ SQL 服务器 2012

Can I use PARTITION BY with a GROUP BY clause? SQL Server 2012

tsql

sql-server-2012

aggregate

partition