2008/10/29 Tom Lane <tgl@sss.pgh.pa.us>:
> "Hitoshi Harada" <umi.tanuki@gmail.com> writes:
>> Can "ROWS" be reserved_keyword?
>
>> In window specifications, we have
>
>> OVER (ORDER BY expr_list [(ROWS|RANGE) ... ])
>
>> and currently "ROWS" is not reserved so bison is confused with cases
>> of "ROWS" included in expr_list and in FRAME clause. Because there is
>> no delimiter between ORDER BY clause and FRAME (that is (ROWS |
>> RANGE)) clause, "ROWS" can be in expr_list as a_expr.
>
> Right offhand, I don't see any alternative but to make both ROWS and
> RANGE reserved. It's pretty annoying since that might break existing
> applications that have been using these as identifiers, but the SQL
> committee seems to care little about that :-(
>
> BTW, finding this sort of problem is exactly why ignoring shift/reduce
> conflicts is a bad idea. You would've ended up with unexpected
> behaviors given the wrong input.
>
I see it now. This is so good study to me, though it spent me much
time. Thanks anyway.
Regards,
--
Hitoshi Harada