Terrible knock-knock jokes

My son has really taken a shine to knock-knock jokes of late.

He's been a fan of these "jokes" for some time. Lately though he's waging a war of attrition against his parents and grandparents.

Now you wouldn't have a problem with this if only the jokes weren't so terrible. Here's a few of his favourites:

Knock knock
Who's there?

Cheese
Cheese who?

Cheese Horse I didn't say chimney

Or this one:

Knock knock
Who's there?

Banana
Banana who?

Banana I bet you didn't think I'd say cheese horse

Anyone else see the problem here?

Now in fairness he's only four-and-a-half and the whole humour thing can be complex. I am prone on occasion to a dash of sarcasm so he might not be completely clear about the whole humour thing yet.

That begs the question though. Do knock-knock jokes exist in some form in parts of the world where English is not the first language?

Is there a Chinese equivalent of the knock-knock joke?
What about Australia, South America, Africa, Central Europe?

I mean these jokes are terrible. Are they terrible elsewhere too?