Dynamic LOV with two static entries

Question

I need an additional static entry in a List of Values field.
As my first static entry I use the Null condition.
Or maybe somebody has a different idea how to accomplish the following:
I want to be able to select all the entries of a table with a certain foreign key, all entries with the "value" NULL or just all entries.
thanks

Answer 1

I ran into more problems but i resolved them :D
Since I want that at the first load 'all values' is selected... I needed to set :P1_SELECT to -1 when its NULL but that got me some trouble with select 'NULL Values'... thus I changed the NULL value of :P1_SELECT to -2.
This solution has also the other convenience that at top of the select box is 'all values', second entry is 'null values' and all the following are build up dynamicly
select d, r from (
select ename d, empno r from emp -- your foreign key condition
union
select 'NULL Values' d, -2 r from dual -- NULL values
union
select 'All values' d, -1 r from dual -- All data condition. Use a return value that is not in the empno domain
default: -1
In your report, create a where condtion like
WHERE (empno = :P1_SELECT AND :P1_SELECT IS NOT NULL) -- foreign key
OR (:P1_SELECT = -2 AND empno IS NULL) -- Null values
OR (:P1_SELECT = -1) -- All values