how to increment the datetime value with the incre

Question

how to increment the datetime value with the increment value as 30 minutes in oracle? In mssql i used the following query for solve my problem, i need the equivalent query in oracle

 with mycte as(
       select cast('2012-01-01 00:00:00' as datetime) DateValue union all 
       select dateadd(minute,30,DateValue) from mycte where  dateadd(minute,30,DateValue) <= '2012-01-01 23:59:00')
 select DateValue from  mycte option (maxrecursion 32767);

result for the above query is as follows:

DateValue
2012-01-01 00:00:00.000
2012-01-01 00:30:00.000
2012-01-01 01:00:00.000
2012-01-01 01:30:00.000
2012-01-01 02:00:00.000
2012-01-01 02:30:00.000
2012-01-01 03:00:00.000
2012-01-01 03:30:00.000
2012-01-01 04:00:00.000
2012-01-01 04:30:00.000
2012-01-01 05:00:00.000
2012-01-01 05:30:00.000
2012-01-01 06:00:00.000
2012-01-01 06:30:00.000
2012-01-01 07:00:00.000
2012-01-01 07:30:00.000
2012-01-01 08:00:00.000
2012-01-01 08:30:00.000
2012-01-01 09:00:00.000
2012-01-01 09:30:00.000
2012-01-01 10:00:00.000
2012-01-01 10:30:00.000
2012-01-01 11:00:00.000
2012-01-01 11:30:00.000
2012-01-01 12:00:00.000
2012-01-01 12:30:00.000
2012-01-01 13:00:00.000
2012-01-01 13:30:00.000
2012-01-01 14:00:00.000
2012-01-01 14:30:00.000
2012-01-01 15:00:00.000
2012-01-01 15:30:00.000
2012-01-01 16:00:00.000
2012-01-01 16:30:00.000
2012-01-01 17:00:00.000
2012-01-01 17:30:00.000
2012-01-01 18:00:00.000
2012-01-01 18:30:00.000
2012-01-01 19:00:00.000
2012-01-01 19:30:00.000
2012-01-01 20:00:00.000
2012-01-01 20:30:00.000
2012-01-01 21:00:00.000
2012-01-01 21:30:00.000
2012-01-01 22:00:00.000
2012-01-01 22:30:00.000
2012-01-01 23:00:00.000
2012-01-01 23:30:00.000

I need the equivalent query in oracle,,

Answer 1

Another way could be

select to_date('2012-01-01', 'yyyy-mm-dd') + (level-1)/48 as datetime 
  from dual
connect by level <= 48

Answer 2

with mycte as (
    select timestamp '2012-01-01 00:00:00' + interval '30' minute * level as DateValue 
    from dual 
    connect by level < 48
)
select *
from mycte;