In a way, yes. EdgeDB implements type inheritance and abstract types, so you can have a schema like:

  abstract type Text:
    link body -> str

  type Post extending Text
  type Comment extending Text
  

And then query Text instances like this:

  SELECT Text {
    body,
    title := 'Post'    IF Text IS Post ELSE
             'Comment' IF Text IS Comment ELSE
             'unknown'
  };