Zoho creator api query where field blank or null?

Zoho creator api query where field blank or null?

I tried posting a long question related to this but it was marked spam so I'll just have to post multiple smaller questions.

I can't seem to figure out how to do an api query where a value is blank or null, not sure how zoho stores it, whether it's blank or null as the underlying value.

What's the proper way to query with criteria this way?