Re: [HACKERS] regular expressions from hell - Mailing list pgsql-hackers

From Jose' Soares Da Silva
Subject Re: [HACKERS] regular expressions from hell
Date
Msg-id Pine.LNX.3.96.980601094840.759A-100000@proxy.bazzanese.com
Whole thread Raw
In response to Re: [HACKERS] regular expressions from hell  ("Thomas G. Lockhart" <lockhart@alumni.caltech.edu>)
List pgsql-hackers
On Sun, 31 May 1998, Thomas G. Lockhart wrote:

> > I've noticed there are no less then 10^10 regex implementations.
> > Is there a standard?  Does ANSI have a regexp standard, or is there
> > a regex standard in the ANSI SQL spec?  What do we use?
>
> afaik the only regex in ANSI SQL is that implemented for the LIKE
> operator. Pretty pathetic: uses "%" for match-all and "_" for match-any
> and that's it. Ingres had a bit more, with bracketed character ranges
> also. None as rich as what we already have in the backend of Postgres.
>
> Don't know about any other ANSI standards for regex, but I don't know
> that there isn't one either...
>
- SQL3 SIMILAR condition.
SIMILAR is intended for character string pattern matching. The difference
between SIMILAR and LIKE is that SIMILAR supports a much more extensive
range of possibilities ("wild cards," etc.) than LIKE does.
Here the syntax:

          expression [ NOT ] SIMILAR TO pattern [ ESCAPE escape ]

                                                      Jose'


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