Question

I have a table TABA(PK:NAME) that stores NAME,NAME_TYPE,SOURCE this way:

NAME  NAME_TYPE SOURCE
----  --------- ------
Name1 Category  S1
Name2 Category  S2
Name3 Datamart  
Name4 Category  S1
Name5 Datamart
Name6 Datamart
Name7 Category  S3

Note above: Only if the NAME_TYPE = Category, then the source is present in the data.

I have another table TABA_PARENT that stores NAME,PARENT_NAME with the relationship between the NAME columns based on the name_type this way.
Datamart to Category relationship is one-to-many.

  NAME   PARENT_NAME
    -----  -----------
    Name3  Name1
    Name3  Name2
    Name3  Name4
    Name3  Name5
    Name5  Name1
    Name5  Name6
    Name6  Name7

My requirement is to get the SOURCE for TABA where NAME_TYPE = Datamart(currently, it is absent in TABA)

Expected Output:

SOURCE column for Name3
-----------------------

S1,S2,S3

The trick is to recursively deduce the SOURCE for the Name3 until it maps to a Category in TABA_PARENT.

In the above example:

Name3 is mapped to PARENT_NAME Name1,Name2,Name4,Name5.
3 of these(name1,Name2,Name4) are of name_type = Category and hence the distinct source is available in TABA — S1,S2
The fourth PARENT_NAME Name5 is a name_type Datamart(source info not available) and needs to be further expanded until it reaches name_type = Category.

We have the information that Name5 is mapped to PARENT_NAME Name1,Name6.
Name1 is a Category and hence source can be deduced.
Name6 is again a Datamart.

But, Name6 ultimately is mapped to Name7 which is a Category, hence source is available — S3

As shown above, all the mappings have to be recursively resolved until they reach name_type Category to identify the distinct sources.

Expected Result: S1,S2,S3 

I am trying if this can be done using listagg or something similar(small pl/sql code would also be ok, but prefer a sinlge select if possible)
I am having difficulty to recursively do this.
Any help would be much appreciated.

Answer 1

Thanks for anyone attempting this.
I tried to use a combination of “connect by” and listagg and achieved the desired result.

select listagg(source,',') within group (order by source) final_source from ( 
select
distinct
b.source source--,
from taba_parent a, taba b
where b.name = a.parent_name
and b.name_type = 'Category'
connect by prior a.parent_name = a.name
start with a.name = 'Name3'        
);