Oracle取前N位SQL

      也许对SQL Server来说,取前N位的数据是很简单的事情,一条TOP语句就搞定了.

      在Oracle中我们往往会感觉到头疼,平日里也常会用到,主要是使用partition by.

语法如下:

select emp_card_no,work_date,read_card_date,count(rownum) as cnt
from hra_read_card_day
group by emp_card_no,work_date,read_card_date
having count () <= 10
order by work_date,read_card_date