優化具有複雜謂詞的MySQL查詢

Question

感謝您試圖提供幫助。我有一個表格，稱爲帖子，每個帖子都有一行。一個帖子有一個post_date（以unix時間戳格式）和一個author_id。

我想獲得按月份和年份分組的一個月內發佈5次或更多次的獨特作者的數量。

查詢我現在有一個獨特的作家通過月份和年份（沒有過濾器在該月內的5支或更多個）是：

select 
    month(from_unixtime(p.post_date)) as month, 
    year(from_unixtime(p.post_date)) as year, 
    count(distinct p.author_id) 
from posts p 
group by month,year 
order by year desc,month desc 

能否請你幫我補充一個過濾器，只算在那個月有5個或更多帖子的作者？

UPDATE

下面的查詢工作，但極其緩慢，增加了對眼前這個月和今年謂詞時也是如此。有人可以想出更好的方法來做到這一點嗎？

select 
    month(from_unixtime(p.post_date)) as month, 
    year(from_unixtime(p.post_date)) as year, 
    count(distinct p.author_id) 
from posts p 
    where (
    select count(*) from posts p2 where p2.author_id=p.author_id 
    and month(from_unixtime(p.post_date))=month(from_unixtime(p2.post_date)) 
    and year(from_unixtime(p.post_date))=year(from_unixtime(p2.post_date)) 
    )>=5 
group by month,year order by year desc,month desc 

Answer 1

您可以使用具有計數> 5。它會解決這個問題

select month(from_unixtime(p.post_date)) as month, 
    year(from_unixtime(p.post_date)) as year, 
    count(p.author_id) c from posts p 
    group by author , month,year having c >5 
    order by year desc,month desc