What is the difference between confluence attachments vs. attachments uploaded by users?

[P]

In Confluence versions 3-6, there are attachments that are built into the system (like global logos and various fav-icons.PNG).  You can see more information about them here: https://confluence.atlassian.com/doc/changing-the-site-logo-138567.html

After Confluence is installed and ready for use, users can begin to upload their own attachments. 

My Question : How can you tell the difference between attachments that come bundled with confluence 6.2 and ones the user uploaded in the database?

In the database, we can run the following query:

SELECT * from CONTENT where CONTENTTYPE='ATTACHMENT'

This gives a list of all the attachments in the database (favicon.PNG files as well as user uploaded ones). 

How do I modify the SQL query to give a list of only user-uploaded attachments? Could it possibly be:

SELECT * from CONTENT where CONTENTTYPE='ATTACHMENT' and spaceid != 0 

I would appreciate an answer from Atlassian database team. 

Thank you.

[Nic Brough -Adaptavist-]

Confluence databases are slightly more clever and explainable than Jira databases, but they still really do have the same attitude that Jira does - it's a data store, not a database, and hence the worst possible way you can possibly try to read the information in it (not data, information).

Too much of the logic is done in the code.

There is no easy way to distinguish between "system", "space", or "page" attachments, let alone the others, or the stuff thrown in by apps.

Whatever you are trying to do here, I would strongly recommend moving to use the REST API instead of database reads.