mysql - 如何獲取每月發佈或評論的獨特活躍用戶數量？

Question

我有以下表格：

內容：CONTENT_ID，USER_ID，POST_DATE

評論：COMMENT_ID，USER_ID，COM​​MENT_DATE

我怎樣才能通過分組活動的唯一用戶的計數月和年？ 活躍將意味着用戶在該月份發佈或評論。

Answer 1

SELECT 
    T.action_year, 
    T.action_month, 
    COUNT(T.user_id) active_users 
FROM 
    (
    SELECT DISTINCT user_id, YEAR(post_date) action_year, MONTH(post_date) action_month FROM content 
    UNION 
    SELECT DISTINCT user_id, YEAR(comment_date) action_year, MONTH(comment_date) action_date FROM comment 
) T 
GROUP BY 
    T.action_year, 
    T.action_month 
ORDER BY 
    T.action_year ASC, 
    T.action_month ASC 

Answer 2

這未經測試。

select count(table1.user_id), table1.user_id 
from table1 table2 
where table1.user_id = table2.user_id 
And table2.comment_date like 'may' 

Answer 3

試試這個

select TO_CHAR(order_dt,'MON-YYYY'), count(distinct User_ID) cnt from [orders] 
where User_ID in 
(select User_ID from 
(select a.User_ID from [orders] a, 
(select a.User_ID,count (a.order_dt) from [orders] a 
where a.order_dt > (select max(b.order_dt)-365 from [orders] b where a.User_ID=b.User_ID) 
group by a.User_ID 
having count(order_dt)>1) b 
where a.User_ID=b.User_ID) a 
) 
group by TO_CHAR(order_dt,'MON-YYYY');