[英]SQL GROUP BY only in subquery
I have a set of datapoints for the number of fans of different accounts for different days belonging to different brands: 我为不同品牌的不同日期的不同帐户的粉丝数量设置了一组数据点:
|brand|account|date|fans|
|-----|-------|----|----|
|Ford |ford_uk|... |10 |
|Ford |ford_uk|... |11 |
|Ford |ford_us|... |20 |
|Ford |ford_us|... |21 |
|Jeep |jeep_uk|... |30 |
|Jeep |jeep_uk|... |31 |
|Jeep |jeep_us|... |40 |
|Jeep |jeep_us|... |41 |
I'm trying to return the total fans by brand, defined as the sum of the max fans for each of the brand's accounts: 我试图按品牌返回粉丝总数,定义为每个品牌帐户的最大粉丝总和:
Ford: 32
Jeep: 72
I tried a subquery like this: 我尝试了这样的子查询:
(SELECT sum(account_fans)
FROM
(
SELECT max(fans) AS account_fans
GROUP BY account
) subquery_name
) AS total_fans
The problem is that I get: 问题是我得到:
ERROR: subquery uses ungrouped column account from outer query.
错误:子查询使用外部查询中的未分组列帐户。
But I don't want to group the outer query. 但我不想将外部查询分组。 Can you help?
你能帮我吗?
You need two levels of subqueries: 您需要两个级别的子查询:
select brand, sum(fans)
from (select brand, account, max(fans) as fans
from account_fans af
group by brand, account
) ba
group by brand;
Have you tried writing your query this way? 您是否尝试过以这种方式编写查询?
select brand, sum(mx)
from (
select brand, account, max(fans) mx
from account_fans
group by brand, account
) t1
group by brand
Try below query : 请尝试以下查询:
SELECT T1.brand, sum(A.maximum)
FROM your_table T1
JOIN
(
SELECT brand, account, max(fans) maximum
FROM your_table T2
GROUP BY brand, account
) A ON T2.brand = T1.brand
GROUP BY brand
Try this: 尝试这个:
-- temporary table like your data ------------
DECLARE @account_fans TABLE(brand NVARCHAR(10),account NVARCHAR(10),fans INT)
INSERT INTO @account_fans VALUES ('Ford', 'ford_uk',10),('Ford', 'ford_uk',11),
('Ford', 'ford_us',20),('Ford', 'ford_us',21),('Jeep', 'jeep_uk',30),
('Jeep', 'jeep_uk',31),('Jeep', 'jeep_us',40),('Jeep', 'jeep_us',41)
-- temporary table like your data ------------
SELECT * FROM @account_fans -- your table
SELECT brand, SUM(fans) fans FROM (
SELECT brand,account,MAX(fans) fans FROM @account_fans GROUP BY account,brand
) A GROUP BY brand -- output you require
Hope it helps. 希望能帮助到你。 :)
:)
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