Oracle 21c

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CREATE FUNCTION GET_LEAST_VALUE(
  in_numbers IN SYS.ODCINUMBERLIST
) RETURN NUMBER
IS
  v_least NUMBER;
BEGIN
  SELECT MIN(column_value)
  INTO   v_least
  FROM   TABLE(in_numbers);

  RETURN v_least;
END;
/
SELECT get_least_value(SYS.ODCINUMBERLIST(15,2,3))
FROM   DUAL;


GET_LEAST_VALUE(SYS.ODCINUMBERLIST(15,2,3))


2


BEGIN
  DBMS_OUTPUT.PUT_LINE(get_least_value(SYS.ODCINUMBERLIST(15,2,3)));
END;
/
1 rows affected

dbms_output:
2