> This isn't a PostgreSQL issue, but rather one of understanding how
> regular expressions work in general. See the previously mentioned
> "Pattern Matching" section of the PostgreSQL documentation for the
> PostgreSQL-specific details, and use a search engine to find a
> regular expression tutorial; they're frequently used in Perl and
> other languages so a lot of learning material exists. If you can
> find a copy in a library or bookstore, the book _Mastering Regular
> Expressions_ by Jeffrey E. F. Friedl, published by O'Reilly, is a
> good resource.
>
If you have Perl installed, do a 'man perlretut'. It is quite a wonderful
tutorial. That is what I used to learn regular expressions.
Yasir