Hey,
Looking again at the SELECT Reference page while helping a novice user I was once again annoyed but how the most common query syntax form for the FROM clause is buried within a bunch of "how to generate a table" detail.
In this specific case I also was trying to describe why when you have three tables to join that you can build a join tree and only actually use a single from_item (IOW, no commas are required/allowed). From there it became clear that from_item is serving two roles here and introducing a structural element (join_expression) to represent the commonly used join tree query form made sense. I then modelled the tree-like nature (using the term recursive for now) explicitly as the left side of the join can be either a new join_expression, extending the tree, or a from_item, bringing the tree to its end.
In the description I had to move LATERAL up above all the join stuff since it pertains to from_item and I wanted to call out the final set of parameters as all being related to the join tree.
I'll do a pass at making sure we are using consistent terminology if this has a shot of getting committed.
I've attached the patch and the resulting html page.
David J.
