Re: New CORRESPONDING clause design

On Tue, Jan 17, 2017 at 12:37 AM, Surafel Temsgen <surafel3000(at)gmail(dot)com> wrote:
> I am new here and I really want to contribute, I have read same resource
> that help understanding database system and postgresql. I would like to
> start implementing sql syntax corresponding by clause because I believe
> implementing sql syntax gives an opportunity to familiarize many part of
> postgresql source code. Previous implementation is here and have an issue on
> explain query and break cases on unlabeled NULLs
> To repeat what a corresponding by clause means
> Corresponding clause either contains a BY(...) clause or not. If it
> doesn't have a BY(...) clause the usage is as follows.

This is great stuff. Does the syntax only apply to UNION? I would
imagine it would also apply to INTERSECT/EXCEPT? What about UNION
ALL?

merlin