On Fri, Jun 21, 2013 at 12:18 AM, Jeff Davis <pg...@j-davis.com> wrote: > On Thu, 2013-06-20 at 10:03 -0400, Robert Haas wrote: >> I think the question is whether this feature is really worth adding >> new reserved keywords for. I have a hard time saying we shouldn't >> support something that's part of the SQL standard, but personally, >> it's not something I've seen come up prior to this thread. > > What's the next step here?
Well, ideally, some other people weigh in on the value of the feature vs. the pain of reserving the keywords. > The feature sounds useful to me. ...and there's one person with an opinion now! :-) The other question here is - do we actually have the grammar right? As in, is this actually the syntax we're supposed to be implementing? It looks different from what's shown here, where the IGNORE NULLS is inside the function's parentheses, rather than afterwards: http://rwijk.blogspot.com/2010/06/simulating-laglead-ignore-nulls.html IBM seems to think it's legal either inside or outside the parentheses: http://pic.dhe.ibm.com/infocenter/informix/v121/index.jsp?topic=%2Fcom.ibm.sqls.doc%2Fids_sqs_2594.htm Regardless of what syntax we settle on, we should also make sure that the conflict is intrinsic to the grammar and can't be factored out, as Tom suggested upthread. It's not obvious to me what the actual ambiguity is here. If you've seen "select lag(num,0)" and the lookahead token is "respect", what's the problem? It sort of looks like it could be a column label, but not even unreserved keywords can be column labels, so that's not it. Probably deserves a bit more investigation... > If the grammar is unacceptable, does > someone have an alternative idea, like using new function names instead > of grammar? If so, what are reasonable names to use? We could just add additional, optional Boolean argument to the existing functions. It's non-standard, but we avoid adding keywords. > Also, I think someone mentioned this already, but what about > first_value() and last_value()? Shouldn't we do those at the same time? Not sure. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers