--- Normalize the child object into child.
SELECT * INTO child FROM objects
INNER JOIN activities ON COALESCE(activities.data->'object'->>'id', activities.data->>'object') = objects.data->>'id'
--- Normalize the child object into child.
SELECT * INTO child FROM objects
INNER JOIN activities ON COALESCE(activities.data->'object'->>'id', activities.data->>'object') = objects.data->>'id'