获取表中的最大记录

问题描述

| 我有这样的表： 餐桌学校

ID_School     name
--------------------
ACH001        jack
ACH001        gon
ACH001        fanny
ACH001        tony
ACH002        vera
ACH002        jessica
ACH003        rey
ACH003        tomy

我想在此表中输出最大记录ID_School，并输出如下所示：

ID_School  count
-----------------
ACH001     4

    

解决方法

在MS SQL中：

select top 1 ID_School,count(*) IdCount
from school
group by ID_School
order by IdCount desc

    ,就是这个：

select ID_school,count(ID_school) as total from school group by names order by total desc limit 1;

    ,对于Oracle：

SELECT id_school,cnt
  FROM (SELECT id_school,count(*) cnt
          FROM school
         GROUP BY id_school
         ORDER BY cnt)
 WHERE ROWNUM = 1;