From: | Christopher Nehren <apeiron+usenet(at)coitusmentis(dot)info> |
---|---|
To: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: Next and previous sequence values |
Date: | 2005-03-16 01:37:05 |
Message-ID: | slrnd3f3ge.1hqu.apeiron+usenet@prophecy.dyndns.org |
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Thread: | |
Lists: | pgsql-novice |
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On 2005-03-15, Michael Fuhr scribbled these
curious markings:
>> I have a table whose rows are distinguished by a sequence. I'd like to
>> be able to, given a certain value of that sequence, retrieve the next
>> and previous values in relation to the given value. Couldn't find
>> anything in the docs for the version that I'm running, 8.0. Thanks in
>> advance.
>
> Maybe this example will help:
>
> CREATE TABLE foo (id integer PRIMARY KEY);
> INSERT INTO foo (id) VALUES (1);
> INSERT INTO foo (id) VALUES (2);
> INSERT INTO foo (id) VALUES (5);
> INSERT INTO foo (id) VALUES (6);
> INSERT INTO foo (id) VALUES (7);
>
> SELECT id FROM foo WHERE id < 5 ORDER BY id DESC LIMIT 1;
> id
> ----
> 2
> (1 row)
>
> SELECT id FROM foo WHERE id > 5 ORDER BY id LIMIT 1;
> id
> ----
> 6
> (1 row)
>
> Is that what you're after? If not then please give an example of
> what you'd like to do.
Yes, that is precisely what I want, and stated quite succinctly. Many
thanks indeed.
Best Regards,
Christopher Nehren
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