Problem in designing an SQL or PL/SQL

Question

Hi all,
This is my problem statement....
I have a query that gives me output like this..i cannot change this query...the result is coming from 2 independent tables.....
accountid effective date term date
1 01/01/07 01/16/07
1 01/01/07 01/20/07
1 01/16/07 01/30/07
1 01/20/07 02/02/07
1 01/30/07 02/02/07
1 02/02/07 NULL
1 02/02/07 NULL
i should have my result as below.
accountid effective date term date
1 01/01/07 01/16/07
1 01/16/07 01/20/07
1 01/20/07 01/30/07
1 01/30/07 02/02/07
1 02/02/07 NULL
i taught of the following logic to derive the output...
will group by accountid and effective date and order by effctive date....change all my term dates to null and load term date from the effective date of the next record...
but i am not able to come up with an SQL or PL/SQL for doing the same..
Can anyone let me know whether it is possible to do this..
Regards
Bharath

Answer 1

Try this. I used analytics. You said you can't change the SQL which produces your source data so replace my test sql with your actual SQL.
with test as (
     select  1 acct_id, to_date('01/01/07','mm/dd/yy') eff_dt, to_date('01/16/07','mm/dd/yy') term_dt from dual
      union all
     select  1 ,to_date('01/01/07','mm/dd/yy'), to_date('01/20/07','mm/dd/yy') term_dt from dual
      union all
     select  1, to_date('01/16/07','mm/dd/yy'), to_date('01/30/07','mm/dd/yy') term_dt from dual
      union all
     select  1, to_date('01/20/07','mm/dd/yy'), to_date('02/02/07','mm/dd/yy') term_dt from dual
      union all
     select  1, to_date('01/30/07','mm/dd/yy'), to_date('02/02/07','mm/dd/yy') term_dt from dual
      union all
     select  1, to_date('02/02/07','mm/dd/yy'), NULL from dual
      union all
     select  1, to_date('02/02/07','mm/dd/yy'), NULL from dual
select acct_id, eff_dt, max (eff_dt) over ( partition by 1 order by acct_id, eff_dt  rows between 1 following and 1 following)
from   test
group  by acct_id, eff_dt
   ACCT_ID EFF_DT    MAX(EFF_D
         1 01/JAN/07 16/JAN/07
         1 16/JAN/07 20/JAN/07
         1 20/JAN/07 30/JAN/07
         1 30/JAN/07 02/FEB/07
         1 02/FEB/07