Parameter and Command Reference > Oracle Connector (CFS) Parameters > FetchTasks/TaskName Parameters > SubTables 

Use this parameter to specify a CSV list of sub tables that can also contain data that link to the main table. These require a separate section in the configuration file detailing how they should be used. For example:
SQL=select * from inventory

SQL=select * from inventory_flow where item_id = @item_id
You can see from the example that the main table has the table flow linked to table inventory. It has its own SQL statement that gets run for every row returned from the main table and it’s template gets merged with the main one. The table gets linked by the item_id column and the connector knows how to do this by replacing any items in the SQL statement marked with an @ with the value from the main table.
So here if the main SQL brought back some rows with the item_id column ranging from 1-10, then for each row, the sub table SQL statement would be run with the first being
select * from inventory_flow where item_id = 1
and the second being
select * from inventory_flow where item_id = 2
and so forth.
TaskName or FetchTasks