Given that the author also wrote https://scattered-thoughts.net/writing/select-wat-from-sql/, I don't think he knows nothing about inner joins. I think he was just using that equivalent form to compare it with the terser `foo.bar.quux`. It is pretty strange to compare it with `fk_join(foo, 'bar_id', bar, 'quux_id', quux)` though, because SQL already has the equivalent `foo JOIN bar USING bar_id JOIN quux USING quux_id`.