2010/1/29 Pavel Stehule <pavel.steh...@gmail.com>: > 2010/1/28 Robert Haas <robertmh...@gmail.com>: >> 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. > > It is only a few lines with zero complexity. > > The main issue of Takahiro proposal is "unclean" behave. > > we can have a content > > c1 c2 > ----------- > c11, c12, > c21, c22 > > and result of string_agg(c1, c2) > > have to be ?? c11 c12 c21 or c11 c22 c21 ?? What if some content of c2 > will be NULL ?? I checked oracle. Oracle doesn't allow variable as > delimiter. We can't check it. But we can fix first value and using it > as constant.
What about get_fn_expr_arg_stable() to check if the argument is stable during aggregate? Regards, -- Hitoshi Harada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
