Hi, all:

Is there any way to do a UNION and use the string operator || ?

I found another way to do this. Its just to fill a combobox, but still
wondering why the problem.

Each half of the UNION works fine on its own.

I keep getting
SQL error code -104
Invalid command
Data type unknown

for the following (its the field with || in it)

select v1.ml_item || '/' || v2.ml_item as Root_Node ,
v1.ml_id as id,
v2.ml_parentid ,
v1.root_id
from masterlibrary v1, masterlibrary v2
where v1.root_id = v2.ml_parentid
and v1.ml_parentid = -1
UNION
select v3.ml_item || '/' as Root_Node ,
v3.ml_id as id,
v3.ml_parentid ,
v3.root_id
from masterlibrary v3
where v3.ml_id = v3.root_id
order by 1

Thanks,

Chuck Belanger