Processing Hierarchy

Question

I have data like below:
Resource_id           Manager_id                  FTE
100                                                1
101                       100                      1
102                       100                      1
103                       100                      1
104                       101                      1
105                       101                      1
106                       104                      1
create table emp_test (resource_id, manager_id, fte) as
select 100, null,1 from dual union all
select 101, 100,1 from dual union all
select 102, 100,1 from dual union all
select 103, 100,1 from dual union all
select 104, 101,1 from dual union all
select 105, 101,1 from dual union all
select 106, 104,1 from dual;I need summarized output like
Resource_id           Resource_id1            Resource_id2           sum(FTE)
100                      101                          104                       2
100                      101                          105                       1
and
Resource_id           Resource_id1            sum(FTE)
100                      101                          4
100                      102                          1
100                      103                          1How to achieve this in SQL?
Regards,
Parag Chaudhari
Edited by: Parag Chaudhari on Jun 4, 2010 1:21 AM
Edited by: Parag Chaudhari on Jun 4, 2010 1:52 AM

Answer 1

Hi,
Thanks for including the CREATE TABLE AS statement; that's very helpful.
Here's one thing you can do:
VARIABLE  levels_to_show     NUMBER
EXEC  :levels_to_show := 3;
WITH     got_tree     AS
     SELECT     REPLACE ( SYS_CONNECT_BY_PATH ( CASE
                                   WHEN  LEVEL <= :levels_to_show
                                   THEN  TO_CHAR (resource_id, '999999')
                              END
                               , '~'
               , '~'
               )     AS path
     ,     fte
     ,     LEVEL          AS lvl
     FROM     emp_test
     START WITH     manager_id     IS NULL
     CONNECT BY     manager_id     = PRIOR resource_id
SELECT       path
,       SUM (fte)     AS total_fte
FROM       got_tree
WHERE       lvl     >= :levels_to_show
GROUP BY  path
ORDER BY  path
;Output:
PATH                            TOTAL_FTE
    100    101    105                   1
    100    101    104                   2If we set :levels_to_show := 2, then the output is:
PATH                            TOTAL_FTE
    100    101                          4
    100    102                          1
    100    103                          1As you can see, this doesn't actually produce separate columns for resource_id, resource_id1, resource_id2, ...
Instead, all the values (however many there may be) are concatenatd into one big string, but formatted so that they appear as different columns.
If you sant, you could add a "header" row to the output that actually had those titles:
PATH                            TOTAL_FTE
resource_id  resource_id1
        100           101               4
        100           102               1
        100           103               1Or, using dynamic SQL, you could split the path column into separate columns.
This assumes you know of some sub-string (I used '~' above) that never appears in resource_id. (If resource_id is a NUMBER, this is no problem.)