Split rows by date.

Question

Hi All,
I need help to split a row by date.
For example.
in the two columns Effictive_start_date and effictive_end_date for the table per_all_people_f
is '01-01-2006' and '01-30-2010' respictivly for one row.
Then the resulting query should return 5 rows one for each year. and effective_end_date should be the last date of the year for each row
Thanks in advance.
Thanks\Kiran S

Answer 1

Something like this:
with sample_data as (select '12002' id, to_date('01-JAN-2006', 'DD-MON-YYYY') start_date, to_date('12-DEC-2010', 'DD-MON-YYYY') end_date from dual union all
                     select '12003' id, to_date('01-NOV-2006', 'DD-MON-YYYY') start_date, to_date('21-DEC-2009', 'DD-MON-YYYY') end_date from dual union all
                     select '12004' id, to_date('13-FEB-2007', 'DD-MON-YYYY') start_date, to_date('13-NOV-2008', 'DD-MON-YYYY') end_date from dual union all
                     select '12005' id, to_date('12-AUG-2008', 'DD-MON-YYYY') start_date, to_date('21-OCT-2008', 'DD-MON-YYYY') end_date from dual),
-- end of mimicking your sample_data
     dummy_years as (select add_months(start_dt, (level - 1)*12) start_dt, add_months(start_dt, level*12) end_dt
                     from   (select trunc(min(start_date), 'yyyy') start_dt,
                                    add_months(trunc(max(end_date), 'yyyy'), 12) end_dt
                             from   sample_data)
                     connect by level < months_between(end_dt, start_dt)/12 + 1)
-- this bit generates a list of years based on the gap between the lowest and highest years present in the sample_data subquery
select sd.id,
       greatest(sd.start_date, dy.start_dt) new_start_date,
       least(sd.end_date, dy.end_dt-1) new_end_date
from   sample_data sd,
       dummy_years dy
where  trunc(sd.start_date, 'yyyy') <= dy.start_dt
and    add_months(trunc(sd.end_date, 'yyyy'), 12) >= dy.end_dt
order by sd.id,
         new_start_date,
         new_end_date;
ID    NEW_START_DATE NEW_END_DATE
12002 01/JAN/06      31/DEC/06  
12002 01/JAN/07      31/DEC/07  
12002 01/JAN/08      31/DEC/08  
12002 01/JAN/09      31/DEC/09  
12002 01/JAN/10      12/DEC/10  
12003 01/NOV/06      31/DEC/06  
12003 01/JAN/07      31/DEC/07  
12003 01/JAN/08      31/DEC/08  
12003 01/JAN/09      21/DEC/09  
12004 13/FEB/07      31/DEC/07  
12004 01/JAN/08      13/NOV/08  
12005 12/AUG/08      21/OCT/08