SQL Server：按国家/地区获取销售百分比

Question

我有一个T-SQL查询，它按国家计算销售总额：

SELECT      
    SUM(F_Sales_Month.Sales_Qty), D_Customer.Country
FROM            
    F_Sales_Month
INNER JOIN 
    D_Customer ON F_Sales_Month.CustomerKey = D_Customer.CustomerKey
GROUP BY 
    D_Customer.Country

结果：

如何获得百分比而非金额？

Answer 1

这可能是效率最高的

exports.myFunc = functions.https.onRequest(async(request, response) => {
const snapshots = await admin.database().ref('/Employees').once('value')

   let data_snap_arr = Object.keys(snapshots.val() || {}) .map(k => snapshots.val()[k]);

await Promise.all(data_snap_arr.map(handleSnapshot))
response.send("WOKAY!")
})

Answer 2

我会使用窗口函数：

SELECT c.Country  SUM(sm.Sales_Qty), 
       SUM(sm.Sales_Qty) * 1.0 / SUM(SUM(sm.Sales_Qty)) OVER () as country_ratio
FROM F_Sales_Month sm INNER JOIN
     D_Customer c
     ON sm.CustomerKey = c.CustomerKey
GROUP BY c.Country;

* 1.0是因为某些数据库进行整数除法。如果你真的想要0到100之间的百分比，那么使用* 100.0。

Answer 3

这应该给出你的百分比

SELECT      sum(F_Sales_Month.Sales_Qty),
            sum(F_Sales_Month.Sales_Qty) / (SELECT sum(Sales_Qty)
                                            FROM F_Sales_Month
                                            INNER JOIN D_Customer ON
                                            F_Sales_Month.CustomerKey = D_Customer.CustomerKey) * 100.0
            as [PERCENT]
            D_Customer.Country
FROM            F_Sales_Month
INNER JOIN D_Customer ON F_Sales_Month.CustomerKey = D_Customer.CustomerKey
GROUP BY D_Customer.Country

使用基于AdventureWorks2017的示例

SQL Fiddle ...