Converting daily date format to Calendar format 466

Question

Hi All,
I need to convert the DAILY DATE FORMAT TO FORMAT 466...
(4 WEEKS IN PERIOD 1,6 WEEKS IN PERIOD 2 ,6 WEEKS IN PERIOD 3,
4 weeks in period 4,6 weeks in period 5,6 weeks in period 6)
I'm thinking buckets. NTILE perhaps?
But how to approach for it..???
Anyone's help will be appreciated.
Regards
Saugata

Answer 1

My example shows how to translate a date into what you call a "week". You'll need some fiddling to I've never heard of 466 format of weeks so it's not something that there is a pre-existing tool for. NTILE is one approach.
This gives every day in 2008 it's correct period - it's a bit messy, but then I'm only doing it to teach myself about NTILE.
with T as (
select to_date('31/12/2007','DD/MM/YYYY')+level dt
       from dual connect by level <=366)
select to_char(dt,'MM') mth, week, min(dt) start_date, max(dt) end_date from (
select  t.dt dt, NTILE(case when mod(to_char(dt,'MM'),3) = 1 then 4 else 6 end  )
                     OVER (partition by to_char(dt,'MM') order by dt asc) week
from t
) group by to_char(dt,'MM'), week
MTH     WEEK     START_DATE     END_DATE
01     1     01/01/2008     08/01/2008
01     2     09/01/2008     16/01/2008
01     3     17/01/2008     24/01/2008
01     4     25/01/2008     31/01/2008
02     1     01/02/2008     05/02/2008
02     2     06/02/2008     10/02/2008
02     3     11/02/2008     15/02/2008
02     4     16/02/2008     20/02/2008
02     5     21/02/2008     25/02/2008
02     6     26/02/2008     29/02/2008
03     1     01/03/2008     06/03/2008
03     2     07/03/2008     11/03/2008
03     3     12/03/2008     16/03/2008
03     4     17/03/2008     21/03/2008
03     5     22/03/2008     26/03/2008
03     6     27/03/2008     31/03/2008
04     1     01/04/2008     08/04/2008
04     2     09/04/2008     16/04/2008
04     3     17/04/2008     23/04/2008
04     4     24/04/2008     30/04/2008
...