Connect by Problems related with ancestors

Question

Hello,
I have a problem with that.
I have a tree saved in a oracle table. Relationships are mantained with ID and PARENT_ID fields. I save information about Product, Subproduct, BasicSubproduct, (... there could be other levels), Part. This is the hierarchy.
For example, a Product is composed by Subproducts, each Subproduct is composed by BasicSubproducts, and so on.
In other hand, I have a table with data of Parts (for example costs of each one).
What I want is to show information of, for example "Car" Product, grouped by Subproduct (this is the immediately lower level of Product). For example for knowing which are the right parts I did that:
select * from
(select * from NODES
connect by parent_id=PRIOR id
start with id=244) t, -- Node of 'Car' Product
datos b
where
b.id=t.id
But what I don't know it's the ancestor related with the part (in this case it should be the id of the Subproduct). What would it be the right manner to achive that?
I'd appreciate your help.
Thanks.

Answer 1

Hi
You can join a hierarchical query as you suggest; you can also use SYS_CONNECT_BY_PATH() to identify the subproduct. Here's the kind of query you need - I've used the HR sample data, but you should be able to transform this into products, subproducts etc
select subproduct.first_name, subproduct.last_name, part.job_id, sum(part.salary), count(distinct part.employee_id)
from employees subproduct
left join (
select level lev
     , sys_connect_by_path(last_name,'/') reportsto
     , sys_connect_by_path(to_char(employee_id,'fm0000'),'/') ancestors
     , substr(sys_connect_by_path(to_char(employee_id,'fm0000'),'/'),7,4) subprodid
     , emp.*
from employees emp
start with employee_id = 100 -- like identifying the product
connect by prior employee_id = manager_id
) part
on part.subprodid = to_char(subproduct.employee_id,'fm0000')
where subproduct.manager_id=100
group by subproduct.first_name, subproduct.last_name, part.job_idYou'll see I've used a fixed format connect_by_path (with 4 digits per level) which makes it easy to pull out the second level.
HTH
Regards Nigel