mysql 中order by 與group by的順序 是：

select
from
where
group by
order by

注意：group by 比order by先執行，order by不會對group by 內部進行排序，如果group by後只有一條記錄，那麼order by 將無效。要查出group by中最大的或最小的某一欄位使用 max或min函式。

例：

select sum(click_num) as totalnum,max(update_time) as update_time,count(*) as totalarticle from article_detail where userid =1 group by userid order by update_time desc