From: Wei Weng <wweng@kencast.com>
To: Bruno Wolff III <bruno@wolff.to>
Cc: pgsql-sql@postgresql.org
Subject: Re: How do you compare (NULL) and (non-NULL)?
Date: Fri, 29 Oct 2004 11:59:15 -0400
Message-ID: <418268D3.3080700@kencast.com> (raw)
In-Reply-To: <20041027153643.GA14288@wolff.to>
References: <417EB238.1000109@kencast.com>
<20041027153643.GA14288@wolff.to>
Bruno Wolff III wrote:
> On Tue, Oct 26, 2004 at 16:23:20 -0400,
> Wei Weng <wweng@kencast.com> wrote:
>
>>In the following query
>>
>>SELECT Parent FROM Channels ORDER BY Parent ASC;
>>
>>If I have a couple of (NULL)s in the field [Parent], they will be listed at
>>the bottom of the query result.
>>
>>Is it because PostgreSQL considers (NULL) as the biggest value? If I run
>>the same query under MSSQL Server 2000, I get the exact opposite result
>>regarding the order of (NULL)s and (non-NULL) values. They are listed at
>>the very beginning of the query result.
>
>
> If the order matters, you can order by IS NULL or IS NOT NULL.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
> joining column's datatypes do not match
>
>
How do I write that?
Thanks
Wei
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To: pgsql-sql@postgresql.org
Cc: wweng@kencast.com, bruno@wolff.to
Subject: Re: How do you compare (NULL) and (non-NULL)?
In-Reply-To: <418268D3.3080700@kencast.com>
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