SQL GROUP BY 仅在子查询中

Question

我有一组属于不同品牌的不同帐户在不同日期的粉丝数量的数据点:

|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  |

我正在尝试按品牌返回粉丝总数，定义为每个品牌账户的最大粉丝数之和:

Ford: 32
Jeep: 72

我试过这样的子查询:

(SELECT sum(account_fans)
  FROM
  (
    SELECT max(fans) AS account_fans
    GROUP BY account
  ) subquery_name
) AS total_fans

问题是我得到:

ERROR: subquery uses ungrouped column account from outer query.

但我不想对外部查询进行分组。你能帮忙吗？

Answer 1

您是否尝试过以这种方式编写您的查询？

select  brand, sum(mx)
from    (
            select  brand, account, max(fans) mx
            from    account_fans
            group by brand, account
        ) t1
group by brand