windows 功能+硬盘分区

Question

我需要做同样的结果，但不是用连接而是 windows 函数 + 分区。输出是年份，客户id和一年中客户利润占所有利润的比率。

year    Customer_ID    ratio          
2012    2              0.0222
2012    4              0.049
2012    37             0.015
2013    2              0.124


this is the join that work


SELECT a.year, a.Customer_ID, a.profit/b.profit as ratio 
FROM (  select year(order_date) as year, Customer_ID, sum(Profit) as profit 
        from [targil 2].[dbo].[exc2 - orders] 
        group by year(order_date) , Customer_ID
        ) A 
CROSS JOIN (select year(order_date) as year, sum(Profit) as profit
            from [targil 2].[dbo].[exc2 - orders]
            group by year(order_date)) B 
            where a.year = b.year;

Answer 1

没有示例数据很难，但是如果您想使用不带 CROSS JOIN 并使用 window 函数的语句，下一条语句可能会有所帮助：

SELECT 
    a.[year], 
    a.Customer_ID, 
    a.profit / SUM(a.profit) OVER (PARTITION BY a.[year]) as ratio 
FROM (
    SELECT 
        YEAR(order_date) as [year], 
        Customer_ID, 
        SUM(Profit) as profit 
    FROM [targil 2].[dbo].[exc2 - orders] 
    GROUP BY YEAR(order_date), Customer_ID
) a

备注：

如果 profit 是一个 int 列，您将需要一个额外的 CONVERT。
关于 SUM 函数的文档指出，" .. order_by_clause 是必需的..."，所以像这样使用 SUM ... OVER ...更接近书籍：SUM(profit) OVER (PARTITION BY [year] ORDER BY (SELECT NULL)).

windows 功能+硬盘分区

windows function + partition hard

sql

windows

sql-server

function

partition