Обсуждение: Question on the use of bracket expressions in Postgres

Good morning,

I am new to Postgres and I have one question.  I am trying to get the
following select command to work.

    select * from catalog where file_name like 'abc%def%.200[2-5]%';
The following select keeps returning "(0 rows)".

I know that there are many rows in my database that should be returned
because I first did a
select * from catalog where file_name like 'abc%def%.200%';

I've tried escaping the [ and ] metacharacters and even the - but I got the
same results: (0 rows).

What is the correct syntax to pull out a range of data from my database?

Thanks.

Jimmy

On Dec 15, 2005, at 0:29 , Jimmy Rowe wrote:

>     select * from catalog where file_name like 'abc%def%.200[2-5]%';
> The following select keeps returning "(0 rows)".

LIKE doesn't consider [2-5] to be a range, but rather the literal
characters '[2-5]'. If you're looking for regex, take a look at the
POSIX regex operator ~

http://www.postgresql.org/docs/current/interactive/functions-
matching.html#FUNCTIONS-POSIX-REGEXP

See if something like file_name ~ 'abc.*def.*\.200[2-5]'

select '2003' ~ '200[2-5]' as "yup", '2006' ~ '200[2-5]' as "nope";
yup | nope
-----+------
t   | f
(1 row)


Michael Glaesemann
grzm myrealbox com

In article <F96F2B16-2A2A-4A28-97E1-1B00C9902808@myrealbox.com>,
Michael Glaesemann <grzm@myrealbox.com> writes:

> On Dec 15, 2005, at 0:29 , Jimmy Rowe wrote:

>> select * from catalog where file_name like 'abc%def%.200[2-5]%';
>> The following select keeps returning "(0 rows)".

> LIKE doesn't consider [2-5] to be a range, but rather the literal
> characters '[2-5]'. If you're looking for regex, take a look at the
> POSIX regex operator ~

> http://www.postgresql.org/docs/current/interactive/functions-
> matching.html#FUNCTIONS-POSIX-REGEXP

> See if something like file_name ~ 'abc.*def.*\.200[2-5]'

That's not quite the same because LIKE matching is anchored.
Try something like file_name ~ '^abc.*def.*\.200[2-5]$'