最も異なる参加者を持つSELECTフォーラムのトピック

Question

私はフォーラムのメンバーに報酬を与えるシステムを構築しています。

私はすでにこの24時間の各フォーラムトピックの投稿（返信）の数を数えます。

SELECT poster . * , count(odgovori.id_odgovor) AS broj, members.username 
FROM poster 
INNER JOIN odgovori ON (odgovori.na = poster.id_poster) 
INNER JOIN members ON (poster.od = members.id_member) 
WHERE poster.datum = '01.06.09' 
GROUP BY odgovori.na, odgovori.od 
ORDER BY broj DESC 
LIMIT 1 

 
table poster - forum topics table 
table odgovori - replies table 
table members - members table, in this query only used to get topic author's username 

Answer 1

SELECT poster.*, COUNT(DISTINCT odgovori.author) AS different 
FROM poster 
JOIN odgovori 
ON  odgovori.na = poster.id_poster 
GROUP BY 
     poster.id 
ORDER BY 
     different DESC 
LIMIT 1