Using the result of a function, inside a subselect

Question

Hi!
I´m wondering if it´s possible to use the result of a function inside a subselect. Let me give you an example of what I´m trying to do here:
select * from t_node where node_pk in (get_node_parents_pk(22345));
The function get_node_parents_pk stands in for the following SELECT-statment:
select node_pk from t_node_child where parent_node_pk = 12345
The statement above would return something like this: 12435,23423,23453,23452
These values represent the node_pk value for the parent nodes.
I want the get_node_parents_pk function to return a result set similar to this so that I might call it inside the IN ( ) statement.
Any clue? =)

Answer 1

I created a collection type in the database:
CREATE OR REPLACE TYPE nodes_pk_arr IS TABLE OF INTEGER;
The function get_node_parents_pk () is made to return the collection type above. However, this does not work. I get the following error message:
SELECT *
FROM t_node
WHERE node_pk IN
(SELECT * FROM TABLE (get_node_parents_pk (22345)));
ORA-22905: cannot access rows from a non-nested table item
However, if I insert a nodes_pk_arr collection directly into the SQL-statement, like I do below, it works:
SELECT *
FROM t_node
WHERE node_pk IN
(SELECT * FROM TABLE (nodes_pk_arr(24564,23545,34523));
So, when returning the collection from the function I´m told that the collection is not a nested table, when in fact it is. What gives?
Also, is there no way to return a result set directly from the get_node_parents_pk() function, making it possible to write the statement like that shown below?
SELECT *
FROM t_node
WHERE node_pk IN (get_node_parents_pk (22345));
Your reply is much appreciated!
Kind regards
Robert