Review: listagg aggregate
in [PgSql]
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From: Alastair Turner on 26 Jan 2010 06:44 On Tue, Jan 26, 2010 at 1:23 PM, Alastair Turner <bell(a)ctrlf5.co.za> wrote: > ..... > > Given that it potentially produces a delimited list, not a straight > conacatenation (and that list is unacceptable since it would be > descriptive as a noun but not as a verb) would implode_agg not be the > most descriptive name? > Actually, scratch that. The other *agg functions are named for what they produce as output. Not for their process - as per the objection to list_agg and suggestions of conact_agg and implode_agg. string_agg would be consistent, which is a wonderful thing if you can get it in a naming scheme. -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Peter Eisentraut on 26 Jan 2010 07:03 On tis, 2010-01-26 at 03:08 -0800, David E. Wheeler wrote: > On Jan 25, 2010, at 23:14, Pavel Stehule <pavel.stehule(a)gmail.com> > wrote: > > > why is concat_agg better than listagg ? > > Because it's an aggregate that cocatenates values. It's not an > aggregate that lists things. I also like concat_agg better than > string_agg because it's not limited to acting on strings. What else can it act on? -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 26 Jan 2010 09:15 On Tue, Jan 26, 2010 at 2:14 AM, Pavel Stehule <pavel.stehule(a)gmail.com> wrote: > 2010/1/25 Robert Haas <robertmhaas(a)gmail.com>: >> On Mon, Jan 25, 2010 at 2:27 PM, David E. Wheeler <david(a)kineticode.com> wrote: >>> On Jan 25, 2010, at 2:09 AM, Peter Eisentraut wrote: >>>> xmlagg -> concatenates values to form xml datum >>>> array_agg -> concatenates values to form array datum >>>> ??? -> concatenates values to form string datum >>> >>> concat_agg(). >> >> I like that one... > > why is concat_agg better than listagg ? Because it doesn't make lists. Honestly, I don't love concat_agg() either - why should something need to have agg in the name just because it's an aggregate? I think the most descriptive name would be something like concatenate_with_separator(), but that's kind of long. ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Pavel Stehule on 26 Jan 2010 09:56 2010/1/26 Robert Haas <robertmhaas(a)gmail.com>: > On Tue, Jan 26, 2010 at 2:14 AM, Pavel Stehule <pavel.stehule(a)gmail.com> wrote: >> 2010/1/25 Robert Haas <robertmhaas(a)gmail.com>: >>> On Mon, Jan 25, 2010 at 2:27 PM, David E. Wheeler <david(a)kineticode.com> wrote: >>>> On Jan 25, 2010, at 2:09 AM, Peter Eisentraut wrote: >>>>> xmlagg -> concatenates values to form xml datum >>>>> array_agg -> concatenates values to form array datum >>>>> ??? -> concatenates values to form string datum >>>> >>>> concat_agg(). >>> >>> I like that one... >> >> why is concat_agg better than listagg ? > > Because it doesn't make lists. > > Honestly, I don't love concat_agg() either - why should something need > to have agg in the name just because it's an aggregate? Â I think the > most descriptive name would be something like > concatenate_with_separator(), but that's kind of long. This is never ending story :) MySQL has function concate_ws - but this function has different semantic. I thing so string_agg is short, and from one view consistent Pavel > > ...Robert > -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: "David E. Wheeler" on 26 Jan 2010 10:24
On Jan 26, 2010, at 4:03, Peter Eisentraut <peter_e(a)gmx.net> wrote: > What else can it act on? Any data type, since they all can be converted to text. Integers would be a common choice. David -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |