2013/8/29 Tom Lane <t...@sss.pgh.pa.us> > Pavel Stehule <pavel.steh...@gmail.com> writes: > > 2013/8/29 Tom Lane <t...@sss.pgh.pa.us> > >> So the question I'm now wondering about is whether this consideration > >> makes variadic aggregates a bad idea all around, even if we don't have > >> any built-in ones. Is the risk of user confusion (in the use of their > >> own aggregate) sufficient reason to reject such a feature? > > > can be this issue solved by syntax? > > In September commitfest is patch for "WITHIN GROUP" where ORDER BY > clause > > is safety separated from parameters. > > That might not be the ugliest syntax the SQL committee ever invented, but > it's right up there. I don't want to go that way, especially not when the > existing precedent for the same feature with regular functions doesn't use > any weird special syntax. >
It is maybe not nice, but it is long years supported by almost all SQL servers. When I talked with Atri, he mentioned, so variadic aggregates are supported there too. Regards Pavel > On further reflection, what the "policy" was actually about was not that > we should forbid users from creating potentially-confusing aggregates > themselves, but only that we'd avoid having any *built in* aggregates with > this hazard. So maybe I'm overthinking this, and the correct reading is > just that we should have a policy against built-in variadic aggregates. > > can be this potentially strange situation identified? - and some warning can be raised. > regards, tom lane >
