sql練習 -----求出發帖最多的人

昨天無意識看到同桌的同事在練習sql，其中看到他在寫一道題的sql，

求出發帖最多的人？

開始我寫的是這句：

select t.authorid,max(total) from (select authorid,count(*) total from articles

group by authorid ) t group by t.authorid 結果去執行，完了，錯的！ 寫了兩句相當於

寫了一句，都是一樣的結果。

正確的寫法如下：

select teaid,count(*) total from articles group by teaid having count(*) =

(select max(total2) from (select count(*) total2 from articles group by teaid) t);

記得不能寫成如下這樣哦：

select teaid,count(*) total from articles group by teaid

having total = //total 一定要寫成 count(*)

(select max(total2) from (select count(*) total2 from articles group by teaid) t);

下面這樣寫直接報錯
select teaid,count(*) total from articles group by teaid having

count(*)=max(total)

也不應該寫成：

select teaid,count(*) total from articles group by teaid

having total = //total 一定要寫成 count(*)

(select max(total2) from (select count(*) total2 from articles group by teaid)

as t);//子查詢不能加as as只能用作表的別名

下面的寫法也會報錯

select teaid , count(*) c from articles group by teaid

having count(*) = select max(t.total) from (select teaid,count(*) total from articles group by teaid) t


應該寫成下面這樣

select teaid , count(*) c from articles group by teaid

having count(*) = (select max(t.total) from (select teaid,count(*) total from

articles group by teaid) t)//應該加上括號