sql - 我如何找到拥有最活跃卖家(每个用户每天最多的软件销售量)的团队？

Question

我如何找到拥有最活跃卖家(每个用户每天最多的软件销售量)的团队？
我想做类似这样的查询，但感觉不太安静，对吧

SELECT users.team_id, count(*) as sales FROM users
INNER JOIN activity ON users.user_id = activity.user_id
WHERE activity.sales = software
GROUP BY users.team_id
ORDER BY sale DESC

我的用户表如下所示:

user_id       team_id  
0               62  
1               32      
2               21      

虽然我的事件表如下所示:

user_id      sale_date              sale
1            2019-05-02 11:02:39    hardware    
2            2018-05-02 11:02:53    software    
2            2019-06-02 11:42:33    software

Answer 1

听起来这是一个循序渐进的查询，所以让我们从最里面的部分开始:获取每个用户每天的销售计数。

SELECT sale_date, user_id, count(*) as sales
WHERE sale = 'software'
GROUP BY sale_date, user_id

那么我们可以 get the most active user for each day :

SELECT DISTINCT ON (sale_date) sale_date, user_id
FROM (
    SELECT sale_date, user_id, count(*) as sales
    WHERE sale = 'software'
    GROUP BY sale_date, user_id
) AS counts_by_date_and_user
ORDER BY sale_date, sales -- consider breaking ties somehow

然后我们可以计算用户一天中最活跃的频率，按此排序，并获取他们的团队 ID。

SELECT team_id, user_id, count(*) as days
FROM (
    SELECT DISTINCT ON (sale_date) sale_date, user_id
    FROM (
        SELECT sale_date, user_id, count(*) as sales
        WHERE sale = 'software'
        GROUP BY sale_date, user_id
    ) AS counts_by_date_and_user
    ORDER BY sale_date, sales -- consider breaking ties somehow
) AS most_active
JOIN users USING (user_id)
GROUP BY user_id
ORDER BY days DESC