Here's an example from the documentation that just reads like a "rough translation of SQL into Python":
select((item.order, item.order.total_price,
sum(item.price * item.quantity))
for item in OrderItem
if item.order.total_price < sum(item.price * item.quantity))
Well, it doesn't seems that "rough" to me, because content of GROUP BY and HAVING sections is determined automatically and there is no need to manually join tables
