On Thu, Jan 28, 2010 at 10:56 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Thu, Jan 28, 2010 at 9:01 AM, Pavel Stehule <pavel.steh...@gmail.com> >> wrote: >>> simplest could not be a best. There have to be only a const >>> expression. But we have not possibility to check it in pg. > >> Well... that's an entirely arbitrary limitation. I admit that it >> doesn't seem likely that someone would want to have a variable >> delimiter, but putting extra effort and code complexity into >> preventing it seems pointless. > > Yeah. The real issue here is that in some cases you'd like to have > non-aggregated parameters to an aggregate, but SQL has no notation > to express that.
Right. > I think Pavel's underlying complaint is that if the delimiter > argument isn't constant, then we're exposing an implementation > dependency in terms of just which values get separated by which > delimiters. The most practical implementation seems to be that > the first-call delimiter isn't actually used at all, and on > subsequent calls the delimiter *precedes* the associated value, > which is a bit surprising given the order in which one writes > them. Not sure if this is worth documenting though. Those two > or three people who actually try it will figure it out soon enough. Yeah, I'm thoroughly unworried about it. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
