It's true there's nothing in the spec preventing from returning that kind of thing, for instance a JSONB column in your underlying RDBMS would probably lead to what you describe, but it's more that when using SQL you can make "anonymous" queries where you say "give me all columns, I'll deal with their names myself", while GQL is more like "give me all these keys" and there's no way to not specify the key. I don't have great language tools to speak precisely here, hope it makes sense.