Selecting from many stages

Question

dear oracle guru's
I have a process which has 5 stages stages are numbered as 1,2,3,4,5
A stage is completed either at 4 or some times at 5
Process Starts at 1 always
then we can proceed to stage 2 then to stage 3 then ....
otherwise after stage 1 we can jump to stage 4 and finish the process
for every stage processed there is start date and end date
if we reach process 4 or 5 but the end is null , then stage is incomplete and so the process . The process is complete only if stage is 4 or 5 and there is a end date .
The stage table has
appli_no, stage_Code,start_date , end _Date
consider a application number say 1455 , this application is pending since at the stage 4 there is no end date
where as application number say 1456 and 1457 is complete and 1458 is incomplete
the data might be as follows
appli_no stage_Code start_date end _Date
1455 1 01-Jan-2010 02-Jan-2010
1455 2 02-Jan-2010 02-Jan-2010
1455 4 02-Jan-2010
1456 1 01-Jan-2010 01-Jan-2010
1456 5 01-Jan-2010 01-Jan-2010
1457 1 03-Jan-2010 03-Jan-2010
1457 4 03-Jan-2010 03-Jan-2010
1458 1 03-Jan-2010 03-Jan-2010
1458 5 03-Jan-2010
i would like to select applino which are complete that is their stage code in 4 or 5 and end date is not null
and application numbers which are not complete that is they can be in any stage
i managed the first one . some how i am not able to manage the second one
kindly pull me out of things
with warm regards
ssr

Answer 1

Maybe
SQL> with t as (
select 1455 appli_no, 1 stage, '01-Jan-2010' start_dt, '02-Jan-2010' end_dt from dual union all
select 1455, 2, '02-Jan-2010', '02-Jan-2010' from dual union all
select 1455, 4, '02-Jan-2010', null from dual union all
select 1456, 1, '01-Jan-2010', '01-Jan-2010' from dual union all
select 1456, 5, '01-Jan-2010', '01-Jan-2010' from dual union all
select 1457, 1, '03-Jan-2010', '03-Jan-2010' from dual union all
select 1457, 4, '03-Jan-2010', '03-Jan-2010' from dual union all
select 1458, 1, '03-Jan-2010', '03-Jan-2010' from dual union all
select 1458, 5, '03-Jan-2010', null from dual union all
select 1459, 1, '03-Jan-2010', '03-Jan-2010' from dual union all
select 1459, 3, '03-Jan-2010', null from dual
select case
          when stage in (4, 5) and end_dt is null then 'Pending'
          when stage in (4, 5) and end_dt is not null then 'Finished'
          else 'In Progress'
       end
          status,
       appli_no,
       stage
from (select t.*, count (*) over (partition by appli_no order by stage desc) rn
      from t t)
where rn = 1
STATUS        APPLI_NO      STAGE
Pending           1455          4
Finished          1456          5
Finished          1457          4
Pending           1458          5
In Progress       1459          3
5 rows selected.