Re: [HACKERS] regular expressions from hell

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'