Re: a question on SQL

Поиск
Список
Период
Сортировка
От Gregory S. Williamson
Тема Re: a question on SQL
Дата
Msg-id 71E37EF6B7DCC1499CEA0316A256832802B3EA12@loki.wc.globexplorer.net
обсуждение исходный текст
Ответ на Re: a question on SQL  (Bruce Momjian <bruce@momjian.us>)
Список pgsql-general
Bruce Momjian wrote:
>
> Tom Lane wrote:
> > "Greg Sabino Mullane" <greg@turnstep.com> writes:
> > >> It's the single most useful non-standard SQL feature postgresql has. It
> > >> is thus simultaneously bad (from a portatbility aspect) and brilliant
> > >> (because it's a million times easier and faster than the alternatives).
> >
> > > You mean second-most useful. LIMIT/OFFSET is the champion, hand down. :)
> >
> > Yeah, but that one's only quasi-non-standard ... several other DBMSes
> > have it too.
>
> I know MySQL has it, and SQL Lite added it.  Which other ones?  Someone
> asked me recently.  I see this chart from Perl documentation:
>
>     > http://search.cpan.org/~davebaird/SQL-Abstract-Limit-0.12/lib/SQL/Abstract/Limit.pm#DESCRIPTION
>
> Oh, and Rasmus Lerdorf told me he invented LIMIT for mSQL, and MySQL
> then added it, and that MySQL added the limit option.
>
> This was interesting in the MySQL manuals:
>
>     For compatibility with PostgreSQL, MySQL also supports the LIMIT
>     row_count OFFSET offset syntax.
>
> Did we add the OFFSET _keyword_.  I remember we had the comma-ed numbers
> backwards, and we had OFFSET, but I thought that keyword came from
> MySQL.  Obviously, they don't think so.

Informix provides the "FIRST" syntax to get the leading rows of a set; I think you have to use cursors to get further
offsetsthough (been a while since I have had to use it), e.g. "SELECT FIRST 10 col1, col2, col3 FROM foo WHERE ...". No
"LAST"either (just tried). 

They have had this since at least IDS 8 and I thing the 7.x series had it as well. No idea where they got it from; I
learnedon Informix so I actually thought it was standard, until reality disabused me of the notion. 

Greg Williamson
DBA
GlobeXplorer LLC


В списке pgsql-general по дате отправления:

Предыдущее
От: "Richard P. Welty"
Дата:
Сообщение: Re: selinux/postgresql/jfs
Следующее
От: Reece Hart
Дата:
Сообщение: Re: MySQL drops support for most distributions