Thanks for comments. I modified the patch.
Tom Lane wrote:
> Atsushi Ogawa <
atsushi.ogawa@gmail.com> writes:
> > (2)About processing when column identifier of SET clause is specified
> > like 'AAA.BBB'. 'AAA' is a composite column now. When an alias for
> > target table is supported, 'AAA' is a composite column or a table.
> > How do we distinguish these?
>
> You don't, which is why you can't put an alias on a SET target.
I stop applying an alias to a SET target.
> Increasing the reserved-ness of SET isn't real attractive either.
OK. I changed the syntax rule of an alias of UPDATE/DELETE target from
ColId to IDENT. This doesn't change reserved words though candidates
of that alias decreases.
--- Atsushi Ogawa