Multiple values from a single function to be used SQL

Question

I have some pl/sql code that calculates multiple values in the same procedure (multiple out parameters).
Now I want to use these separate values in an SQL select.
One way to do it, is creating functions for each separate value.
Performance wise, I don't want to do so.
I created an object type with 9 number values.
A function returns the object type and I select it in a subquery.
The outer query then selects 3 different values from the object in the subquery.
Unfortunately, a query with 3 rows still results in the function being called 9 times (3 row x 3 values).
Is there a way to force the object function being called just once per row ?
Or is there an alternative way?
I've tried pipelined functions but then I have trouble with the input values for the function that should be taken from another select.
result will be a view with a key value and the calculated values
SELECT key_value, calculated_value1, calculated_value2, calculated_value3
FROM SOME_TABLE

Answer 1

DROP TABLE TBL
CREATE TABLE TBL(
ID NUMBER(10),
CODE VARCHAR2(20),
PARENT NUMBER(10)
INSERT INTO TBL VALUES(1,'A',1);
INSERT INTO TBL VALUES(2,'B',1);
INSERT INTO TBL VALUES(3,'C',1);
INSERT INTO TBL VALUES(4,'D',2);
INSERT INTO TBL VALUES(5,'E',2);
INSERT INTO TBL VALUES(6,'F',2);
CREATE OR REPLACE PACKAGE pck_test IS
TYPE t_rec IS RECORD(
value1 NUMBER,
value2 NUMBER,
value3 NUMBER);
TYPE t_tab IS TABLE OF pck_test.t_rec;
FUNCTION calculate(i_id NUMBER) RETURN pck_test.t_tab
PIPELINED;
END pck_test;
CREATE OR REPLACE PACKAGE BODY pck_test IS
FUNCTION calculate(i_id NUMBER) RETURN pck_test.t_tab
PIPELINED IS
v_return t_rec;
BEGIN
v_return.value1 := 1 * i_id;
v_return.value2 := 2 * i_id;
v_return.value3 := 3 * i_id;
PIPE ROW(v_return);
RETURN;
END;
END pck_test;
now I can use the pipelined function:
SELECT 1 id, x.value1, x.value2, x.value3
FROM TABLE(pck_test.calculate(1)) x
id is hard-coded in this select with value 1
I want to use TBL.id as the argument for the calculate function.
I don't know how. I tried this...
SELECT parent, ID, multi_values.value1, multi_values.value2, multi_values.value3
FROM (
SELECT ID, TABLE(pck_test.calculate(ID)) multi_values
FROM TBL)
Then the SELECT will be stored as a view.
In an application, the view will be queried:
select value1, value2, value3
from view
where parent = :parameter