How to calculate level summary in Hierarchical tables by level

Question

Hi ,
We all know how to present the data in hieararchical tables using CONNECT BY PRIOR and START WITH clause.
Did anybody get the sum on each level , rolling up this informations up to Top level.
Ex. Table Project_Task
(Task_id number,
Task_name varchar2(20),
Parent_task_id number,
Budget number).
Need to get report having sum(budget) on different level.
Level Task Name Total Budget
-----------------------------------------

Answer 1

I don't have 8.1.7 to test with anymore, but as I recall, you can create a new table from a join of your original tables, then query the new table. I believe you could also create a temporary table and insert into it, then select from that. What I am not sure about is whether 8.1.7 will allow the hierarchical subquery in the select clause or not. Please test the following and let us know. If not, then you will probably have to use PL/SQL.
scott@ORA92> -- test data:
scott@ORA92> CREATE TABLE task_id_hierarchy
  2  AS
  3  SELECT empno task_id,
  4           ename task_name,
  5           mgr   parent_task_id
  6  FROM   emp
  7  /
Table created.
scott@ORA92> CREATE TABLE budget_data
  2  AS
  3  SELECT empno task_id,
  4           sal   budget
  5  FROM   emp
  6  /
Table created.
scott@ORA92> -- additional table and query:
scott@ORA92> CREATE GLOBAL TEMPORARY TABLE project_task
  2  AS
  3  SELECT tih.task_id,
  4           tih.task_name,
  5           tih.parent_task_id,
  6           bd.budget
  7  FROM   task_id_hierarchy tih, budget_data bd
  8  WHERE  tih.task_id = bd.task_id
  9  /
Table created.
scott@ORA92> INSERT INTO project_task
  2  SELECT tih.task_id,
  3           tih.task_name,
  4           tih.parent_task_id,
  5           bd.budget
  6  FROM   task_id_hierarchy tih, budget_data bd
  7  WHERE  tih.task_id = bd.task_id
  8  /
14 rows created.
scott@ORA92> SELECT     LEVEL,
  2            task_name,
  3            budget,
  4            (SELECT     SUM (NVL (budget, 0))
  5             FROM         project_task t2
  6             START WITH t2.task_id = project_task.task_id
  7             CONNECT BY PRIOR t2.task_id = t2.parent_task_id) total_budget
  8  FROM     project_task
  9  START WITH parent_task_id IS NULL
10  CONNECT BY PRIOR task_id = parent_task_id
11  /
     LEVEL TASK_NAME      BUDGET TOTAL_BUDGET
         1 KING             5000        29025
         2 JONES            2975        10875
         3 SCOTT            3000         4100
         4 ADAMS            1100         1100
         3 FORD             3000         3800
         4 SMITH             800          800
         2 BLAKE            2850         9400
         3 ALLEN            1600         1600
         3 WARD             1250         1250
         3 MARTIN           1250         1250
         3 TURNER           1500         1500
         3 JAMES             950          950
         2 CLARK            2450         3750
         3 MILLER           1300         1300
14 rows selected.