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* Regular Expression Match Operator escape character
@ 2010-12-08 13:51 Gnanakumar <gnanam@zoniac.com>
0 siblings, 1 reply; 2+ messages in thread
From: Gnanakumar @ 2010-12-08 13:51 UTC (permalink / raw)
To: pgsql-sql
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?
Regards,
Gnanam
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Regular Expression Match Operator escape character
@ 2010-12-13 09:18 Jasen Betts <jasen@xnet.co.nz>
parent: Gnanakumar <gnanam@zoniac.com>
0 siblings, 0 replies; 2+ messages in thread
From: Jasen Betts @ 2010-12-13 09:18 UTC (permalink / raw)
To: pgsql-sql
On 2010-12-08, Gnanakumar <gnanam@zoniac.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.
--
⚂⚃ 100% natural
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2010-12-08 13:51 Regular Expression Match Operator escape character Gnanakumar <gnanam@zoniac.com>
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