[seer]

I think this guide misses the point that “JOIN” is not a root keyword but a modification on “FROM”. It is more akin to logical “AND”, “OR”, etc.

And this stacks much better once you start doing complex joins especially when you can add parentheses to change where you actually join

    FROM a JOIN b JOIN c

Can be different than

    FROM a JOIN (b JOIN C)

Apart from that I think I came up independently to the exact same rules when building the prettier extension for SQL a few years back.

[steve_gh]

SQLis based on set theory, which is asdociative. So (a JOIN b) JOIN c = a JOIN (b JOIN c)

Your DB's query planner should optimise given the available indices.