categories from customLabels, in SOQL

I need to find the categories in my labels. So,

Starting from SOQL to query Custom Labels in Salesforce

and the documentationhttps://developer.salesforce.com/docs/atlas.en-us.api_meta.meta/api_meta/meta_customlabels.htm#!

I torn on tooling, and try this query:

Select Id, Name, ManageableState, NamespacePrefix, value FROM CustomLabel where NamespacePrefix = null

It works, and i get the expected results, as we are already using lots of labels in visualforce. But now i need also the cateories, associated with those labels. So i try:

Select Id, Name, ManageableState, NamespacePrefix, value, categories FROM CustomLabel where NamespacePrefix = null

and i get:

No such column 'categories' on entity 'ExternalString'. If you are attempting to use a custom field, be sure to append the '__c' after the custom field name. Please reference your WSDL or the describe call for the appropriate names.

But it's right there in documentation!