On Dec 13, 2011, at 8:09, Szymon Guz <mabew...@gmail.com> wrote:
>
>
> On 13 December 2011 14:04, InterRob <rob.mar...@gmail.com> wrote:
> Dear List,
>
> I found this interesting:
>
> SELECT regexp_matches('123-A' , E'(3[A-Z\- ])');
> ERROR: invalid regular expression: invalid character range
>
> whereas:
> SELECT regexp_matches('123-A' , E'(3[\- A-Z])');
> regexp_matches
> ----------------
> {3-}
> (1 row)
>
> Notice the order of (escaped) characters and ranges in the last bit of the
> expression.
>
> Am I missing some key concept of the regular expression?
>
> Regards,
> Rob
>
> Hi Rob,
> try '\\-' instead of '\-'
> and it works :)
>
> regards
>
If you don't intend to use PostgreSQL escapes in your string then omit the
leading 'E'.
In a character class the - symbol has special meaning if it appears anywhere
but the first character of the group. To avoid that special meaning you have to
escape it. If it appears first it always means a literal -. The PostgreSQL
documentation does not fully describe RegularExpressions but a reference book
on them would note this particular behavior.
David J.
