Rounding Time to nearest 30 minutes

Question

Good day,
I'm looking for a way to round the time portion of a date value. My query needs to return the time of day, rounded to the nearest 30 minutes - top of the hour or bottom of the hour.
If sysdate is: 12/28/2009 11:08:19 AM
I need to see: 12/28/2009 11:00:00 AM
If sysdate returns: 12/28/2009 11:18:19 AM
I need to see: 12/28/2009 11:30:00 AM
Any help is appreciated.
Regards,
Gary F.

Answer 1

Aketi Jyuuzou wrote:
I like case expression B-)Me too, but I like then simple B-) :
with dates as ( -- generating sample data
select to_date('12/28/2009 11:08:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all
select to_date('12/28/2009 11:18:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all
select to_date('12/28/2009 11:38:19', 'mm/dd/yyyy hh:mi:ss') dt from dual union all
select to_date('12/28/2009 11:48:19', 'mm/dd/yyyy hh:mi:ss') from dual)
select dt,
case when to_char(dt,'mi') >= '45'
     then trunc(dt,'hh') + interVal '60' minute
     when to_char(dt,'mi') >= '15'
     then trunc(dt,'hh') + interVal '30' minute
     else trunc(dt,'hh')
     end as new
  from dates
DT                  NEW
2009-12-28 11:08:19 2009-12-28 11:00:00
2009-12-28 11:18:19 2009-12-28 11:30:00
2009-12-28 11:38:19 2009-12-28 11:30:00
2009-12-28 11:48:19 2009-12-28 12:00:00
SQL> SY.