I'm not Jamie but I think the point is just that this is an awkward way to represent one-to-many relationships. Even with left joins things are even clunkier b

I'm not Jamie but I think the point is just that this is an awkward way to represent one-to-many relationships. Even with left joins things are even clunkier because you no longer have the clunky but straightforward n * m formula for number of rows, you have something even more confusing: n * max(1, m)