在每个子值旁边显示父值的平均值 [英] Display average value of parent values next to each sub value
问题描述
CREATE TABLE Campaigns (
Campaign_ID VARCHAR(255),
Campaign_Category VARCHAR(255),
Sales_Volume VARCHAR(255),
Sales_Quantity VARCHAR(255)
);
INSERT INTO Campaigns
(Campaign_ID, Campaign_Category, Sales_Volume, Sales_Quantity)
VALUES
("C001", "Fashion", "500", "10"),
("C002", "Fashion", "100", "20"),
("C003", "Sport", "800", "15"),
("C004", "Sport", "300", "90"),
("C005", "Sport", "700", "80"),
("C006", "Shoes", "200", "100"),
("C007", "Shoes", "400", "50");
在表中我有不同的campaigns
和相应的campaing_categories
.
现在我想获取每个 Campaign_Category
的 average_sales_price
并将其显示在每个 Campaign_ID
旁边.
预期结果应如下所示:
In the table I have different campaigns
and corresponding campaing_categories
.
Now I want to get the average_sales_price
per Campaign_Category
and display this it next to each Campaign_ID
.
The expected result should look like this:
CampaingID Campaign Category average_sales_price
C001 Fashion 20
C002 Fashion 20
C003 Sport 9.72
C004 Sport 9.72
C005 Sport 9.72
C006 Shoes 4
C007 Shoes 4
通过以下查询,我只能获得每个 Campaign_ID
的 average_sales_price
:
With the following query I only get the average_sales_price
per Campaign_ID
:
SELECT
Campaign_ID,
Campaign_Category,
SUM(Sales_Volume) / SUM(Sales_Quantity) AS Average_Sales_Price
FROM Campaigns
GROUP BY 1;
如何修改我的查询以在每个 Campaign_ID
旁边显示相应 Campaign_Category
的 average_sales_price
?
How do I have to modify my query to display the average_sales_price
of the corresponding Campaign_Category
next to each Campaign_ID
?
推荐答案
可以使用关联子查询:
SELECT C.Campaign_ID, C.Campaign_Category,
(SELECT SUM(CC.Sales_Volume) / SUM(CC.Sales_Quantity)
FROM Campaigns CC
WHERE CC.Campaign_Category = C.Campaign_Category
) AS average_sales_price
FROM Campaigns C;
这里是 SQL Fiddle.
注意:不要在GROUP/ORDER BY
子句中使用列位置,如果在SELECT
语句中更改列位置,则查询将无法生成预期结果.因此,全部限定列名.
Note : Do not use column position in GROUP/ORDER BY
clause, if you change the column position in SELECT
statement then query will fail to generate expected result. So, all qualify column name instead.
这篇关于在每个子值旁边显示父值的平均值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!