Re: how to test string against regular expression contained

On Thu, 25 Mar 2004, Joe Bordes wrote:

> CoL <col@mportal.hu> wrote in message news:<c3s060$1k0m$1@news.hub.org>...
> >
> > create a function for that.
> >
> > create or replace function osregexp(varchar,varchar) returns boolean as
> > ' select $1 ~ $2; 'language sql immutable;
> >
> > SELECT osregexp('windows9x','win.*9x');
> >   osregexp
> > ----------
> >   t
> >
> > C.
>
> Hi,
>
> First thanks for answering.
>
> This gives me the same error. I have created the function as you say
> and it works when called directly with strings (as above) but not when
> called with a table field.
>
> select os_name from table where osregexp('windows9x',os_regexp);
> ERROR: invalid regular expression: empty expression or subexpression

Do you have any strings where the above error might be true?  For example
an empty string or something containing () or other such special values?