How to query all Incidents which have file attachments using a Tabular query in REST API?

Summary:

How to query all Incidents which have file attachments using a Tabular query in REST API? 

Content (required):

How to query all Incidents which have file attachments using a Tabular query in REST API? 

I know how to define a time frame and narrow down the category, but can't translate something like 'where fileattachment = null' or fileattachment.lenght = 0

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Code Snippet (add any code snippets that support your topic, if applicable):

https://xxxxxxx.org/services/rest/connect/latest/queryResults?query=SELECT id FROM incidents where [[fileattachments=0']]???