更改時間戳粒度

Question

如何更改Oracle中時間戳的粒度？

例如：

28.10.2013 15:15:15 

到

28.10.2013 15:00:00 

Answer 1

您將使用trunc命令

的樣本數據：

with dates as (-- generating sample data 
select to_date('10/28/2013 09:08:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all 
select to_date('10/28/2013 09:18:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all 
select to_date('10/28/2013 09:38:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all 
select to_date('10/28/2013 09:48:19', 'mm/dd/yyyy hh:mi:ss') from dual) 

查詢運行：

個

select dt, 
    trunc(dt,'hh') as new_dt 
from dates 

結果

DT     new_dt 
-------------------- ------------------- 
2013-10-28 09:08:19 2013-10-28 09:00:00 
2013-10-28 09:18:19 2013-10-28 09:00:00 
2013-10-28 09:38:19 2013-10-28 09:00:00 
2013-10-28 09:48:19 2013-10-28 09:00:00