docs: using or across embedded resources

docs/references/api/resource_embedding.rst

@@ -852,6 +852,8 @@ An ``or`` filter  can be used for a similar operation:
 
   curl "http://localhost:3000/films?select=*,roles(*)&roles.or=(character.eq.Gummo,character.eq.Zeppo)"
 
+However, this only works for columns inside ``roles``. See :ref:`how to use "or" across multiple resources <or_embed_rels>`.
+
 Limit and offset operations are possible:
 
 .. code-block:: bash
@@ -951,6 +953,18 @@ Both ``is.null`` and ``not.is.null`` can be included inside the `or` operator. F
 
   curl "http://localhost:3000/films?select=title,actors(*),directors(*)&or=(actors.is.null,directors.is.null)"
 
+.. _or_embed_rels:
+
+OR filtering across Embedded Resources
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can also use ``not.is.null`` to make an ``or`` filter across multiple resources.
+For instance, to show the films whose actors **or** directors are named John:
+
+.. code-block:: bash
+
+  curl "http://localhost:3000/films?select=title,actors(),directors()&directors.first_name=eq.John&actors.first_name=eq.John&or=(directors.not.is.null,actors.not.is.null)"
+
 .. _empty_embed:
 
 Empty Embed