From: | Thom Brown <thom(at)linux(dot)com> |
---|---|
To: | Machiel Richards <machielr(at)rdc(dot)co(dot)za> |
Cc: | "pgsql-novice(at)postgresql(dot)org" <pgsql-novice(at)postgresql(dot)org> |
Subject: | Re: Selecting the last 2 rows of a table |
Date: | 2010-11-09 09:42:22 |
Message-ID: | AANLkTin-wf_NLbttk+OzzL-yFfTr96h9PHCMgg-7Bq_D@mail.gmail.com |
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Lists: | pgsql-novice |
On 9 November 2010 09:34, Machiel Richards <machielr(at)rdc(dot)co(dot)za> wrote:
> Good day all
>
> I am trying to find out how I can select the last 2 or (n amount ) of
> rows from a specific table.
>
> We have a table which has been growing rediculously the last view
> days (I must say after a code go-live).
>
> I am trying to find out what data is being written to the table that
> is causing this, however due to the size of the table at the moment, it can
> cause problems so I am just interested in the last number of records.
>
>
> I would appreciate any assistance in this.
>
Well, you'll have to decide what determines the order of your tuples. If
you have a column bound to a sequence, and that is considered to put them in
order, then it would be
SELECT my_columns
FROM my_table
ORDER BY sequence_column DESC
LIMIT 2
Or you could replace that with a date field if appropriate. But whatever
column you use, you'd need an index on it.
--
Thom Brown
Twitter: @darkixion
IRC (freenode): dark_ixion
Registered Linux user: #516935
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