From: | Nikolay Samokhvalov <samokhvalov(at)gmail(dot)com> |
---|---|
To: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: changing null-values' sort order |
Date: | 2005-11-20 09:01:17 |
Message-ID: | e431ff4c0511200101o392a9fbh@mail.gmail.com |
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Thread: | |
Lists: | pgsql-novice |
unfortunately, standard 'nulls first/last' isn't supported yet.
to change behaviour you should use following statement:
select v_date, v_userid from votes order by v_date is not null desc, v_date desc
or, something like this:
select v_date, v_userid from votes order by coalesce(v_date, XXX) desc
where XXX is substituted by the date value that is smaller than any
other used in your table
On 20/11/05, me(at)alternize(dot)com <me(at)alternize(dot)com> wrote:
>
> hi list
>
> coming from the MS-SQL Server world, we're migrating our applications slowly
> to pgsql 8.1. now we thumbled on a problem with different sort-order
> behaviours:
>
> we got a table with dated records:
> table: votes (v_userid, v_date)
>
> the v_date field can either be null or a date in the past. in mssql, sorting
> the table to list records in descending date-order
>
> select v_date, v_userid from votes order by v_date desc
>
> produces a list where first the records with dates are listed, and then the
> ones with nulls. in pgsql, the null-records are listed first before the
> date-records... how can this behaviour be changed?
>
> mssql:
> --------
> 2005-11-05 3
> 2005-11-01 4
> 2005-09-10 1
> null 2
> null 5
>
>
> pgsql:
> --------
>
> null 2
> null 52005-11-05 3
> 2005-11-01 4
> 2005-09-10 1
>
> thanks in advance,
> thomas
--
Best regards,
Nikolay
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