PIE Graph does not return when values = 0

Question

I use this code to create a PIE Chart
select null LINK
,'E0' LABEL
,(select count(*)
from parts
where om_geometry like 'E0'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid) VALUE
from parts where childid = :P1_SELECTED_NODE
union
select null LINK
,'E1' LABEL
,(select count(*)
from parts
where om_geometry like 'E1'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid) VALUE
from parts where childid = :P1_SELECTED_NODE
union
select null LINK
,'E2' LABEL
,(select count(*)
from parts
where om_geometry like 'E2'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid) VALUE
from parts where childid = :P1_SELECTED_NODE
union
select null LINK
,'E3' LABEL
,(select count(*)
from parts
where om_geometry like 'E3'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid) VALUE
from parts where childid = :P1_SELECTED_NODE
union
select null LINK
,'E4' LABEL
,(select count(*)
from parts
where om_geometry like 'E4'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid) VALUE
from parts where childid = :P1_SELECTED_NODE
It works beautifully, except when each of the values returned equate to zero.
When this is the case the svg chart is not returned. Any ideas?

Answer 1

That will come in handy. I have some line graphs to do as well. I am using version 2.2 so i don't think they fixed it. However, i have some good news i have found a work around to my problem. With my set of data i am always going to be bringing back at max 5 values for the data, so i created an item type for each one and set a value in a temporary table. e.g.
declare
l_id number;
begin
delete from graph_temp where name like 'E0' and graph_name like 'P1_GEOM';
select count(*) into l_id
from parts
where om_geometry like 'E0'
start with childid = :P1_SELECTED_NODE
connect by prior childid = parentid;
if l_id > 0 then
insert into graph_temp (name,value, graph_name) values ('E0',l_id,'P1_GEOM');
end if;
return l_id;
end;
As you can see the table only gets populated when the value is greater than zero. My graph then becomes a simple select from the graph_temp table. The only change i now need to make is to have a session id column in the graph_temp table so i only remove the correct session info each time.