Re: Regular Expression Match Operator escape character

On 2010-12-08, Gnanakumar <gnanam(at)zoniac(dot)com> wrote:
> Hi,
>
> We're running PostgreSQL v8.2.3 on RHEL5.
>
> In some places in our application, we use Regular Expression Match Operator
> (~* => Matches regular expression, case insensitive) inside WHERE criteria.
>
> Example:
> SELECT ...
> FROM ...
> WHERE (SKILLS ~*
> '(^|\\^|\\||[^0-9|^a-z|^A-Z]|$)C#(^|\\^|\\||[^0-9|^a-z|^A-Z]|$)'
> OR SKILLS ~*
> '(^|\\^|\\||[^0-9|^a-z|^A-Z]|$).NET(^|\\^|\\||[^0-9|^a-z|^A-Z]|$)')
>
> In this case, we're trying to search/match for either "C#" OR ".NET" in
> SKILLS column.
>
> My question here is, do I need to escape the characters "#" and "." here?

yes. ( '.' especially, I don't think '#' has a special meaning in regex)
but as postgres uses posix extended regex simply escaping every non-letter
character is safe.

(^|\\^|\\||[^0-9|^a-z|^A-Z]|$)

seems to be another way to write

(^|$|[^0-9a-zA-Z])

both of which are locale dependant but that may not be an issue for you.

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