derive query on related tables

 Hi ,

I am working on a script that will take a table name and query as inputs. The script will export data subset from this table and all related tables in the dependency chain.

The script will traverse all parent and children tables recursively and  generate query on a dependent table in the hierarchy.  What is the best method to deduce a query at dependent table?

what are the trade off to choose Join Vs In?

For e.g:

ORDER_DETAILS, query1= where order_date < sysdate - 2 

ORDERS,  query2 = where ORDER_ID in (select order_id from ORDER_DETAILS  <query1>)