I want to use the searchRecords method ( https://www.zoho.com/crm/help/api/searchrecords.html) to include multiple criteria.

I am able to do so, however I do not see anywhere document as how to search "empty" or null? As well as "starts with".

The format in the example in the docs is:

(Field Name:Value)

Is it possible to search for a field name that is not empty? e.g. (Lead Source:Not Null) - something like this?

Thanks