You don't need thge union since you have 0 row in the loop table and when the tag don't have a loop the view will pick the servce from loop_id = 0.

To check if you had missing row in the loop you need to run the following:

select cmpnt_id,loop_id from component c where not exists(select 'x' from loop where c.loop_id = loop_id);

Ilan

Oh Edgeledge... its not even Friday yet man...

What if there are several tag numbers from component table that has loop_id=0 since they are users creating those tags without creating its loop first or not even trying to associate their tags with their loop. And sometime the early days when we use INtools the loop service is often left blank... right !