检查当前日期是否在Oracle SQL的两个日期之间

Question

如果当前日期在Oracle SQL的2个日期之间，我想选择1。

我在阅读完其他问题后写了一篇SQL。

https://stackoverflow.com/questions/2369222/oracle-date-between-query

https://stackoverflow.com/questions/2399753/select-from-table-by-knowing-only-date-without-time-oracle

但它只返回null。 sysdate是日期格式为01/05/2014的当前日期DD/MM/YYYY。

我写的SQL是：

select 1 from dual 
WHERE to_date(sysdate,'DD/MM/YYYY') 
BETWEEN TO_DATE('28/02/2014', 'DD/MM/YYYY')
AND TO_DATE('20/06/2014', 'DD/MM/YYYY');

和

select 1 from dual 
WHERE to_date(sysdate,'DD/MM/YYYY') >= TO_DATE('28/02/2014', 'DD/MM/YYYY') 
AND to_date(sysdate,'DD/MM/YYYY') < TO_DATE('20/06/2014', 'DD/MM/YYYY'); 

Answer 1

您无需将to_date()应用于sysdate。它已经存在了：

select 1
from dual 
WHERE sysdate BETWEEN TO_DATE('28/02/2014', 'DD/MM/YYYY') AND TO_DATE('20/06/2014', 'DD/MM/YYYY');

如果您担心日期中的时间组件，请使用trunc()：

select 1
from dual 
WHERE trunc(sysdate) BETWEEN TO_DATE('28/02/2014', 'DD/MM/YYYY') AND
                             TO_DATE('20/06/2014', 'DD/MM/YYYY');

Answer 2

SELECT to_char(emp_login_date,'DD-MON-YYYY HH24:MI:SS'),A.* 
FROM emp_log A
WHERE emp_login_date BETWEEN to_date(to_char('21-MAY-2015 11:50:14'),'DD-MON-YYYY HH24:MI:SS')
AND
to_date(to_char('22-MAY-2015 17:56:52'),'DD-MON-YYYY HH24:MI:SS') 
ORDER BY emp_login_date

Answer 3

TSQL：日期-需要查找两个日期之间的日期差距

select
distinct
e1.enddate,
e3.startdate,
DATEDIFF(DAY,e1.enddate,e3.startdate)-1 as [Datediff]
from #temp e1 
   join #temp e3 on e1.enddate < e3.startdate          
       /* Finds the next start Time */
and e3.startdate = (select min(startdate) from #temp e5
where e5.startdate > e1.enddate)
and not exists (select *  /* Eliminates e1 rows if it is overlapped */
from #temp e5 
where e5.startdate < e1.enddate and e5.enddate > e1.enddate);