找出员工表中各月最后一天受雇的所有雇员？？？

Question

hiredate 是日期型
select emp.* from empn where hiredate = last_day(hiredate)

Answer 1

或者select emp.* from emp where trunc(hiredate) = trunc(last_day(hiredate))
trunc 截掉时分秒

Answer 2

select emp.* from emp, (select max(hiredate) hiredate, trunc(hiredate, 'month') mm from emp group by trunc(hiredate, 'month')) a where emp.hiredate=a.hiredate;

Answer 3

select emp.* from emp where to_char(hiredate,'yyyymmdd') = to_char(last_day(hiredate),'yyyymmdd')

Answer 4

select * from emp where to_char(hiredate,'yyyymmdd') = to_char(last_day(hiredate),'yyyymmdd')

Answer 5

select emp.* from emp where trunc(hiredate) =(select trunc(max(hiredate)) from emp);

Answer 6

每个月最后1天受雇的？？有点歧义
select * from(
select emp.*,rank() over(partition by trunc(hiredate,'month') order by trunc(hiredate)desc) rk
) where rk = 1