Re: When is a blank not a null or ''

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От mike
Тема Re: When is a blank not a null or ''
Дата
Msg-id 1107343473.21155.18.camel@datacc
обсуждение исходный текст
Ответ на Re: When is a blank not a null or ''  (Alban Hertroys <alban@magproductions.nl>)
Ответы Re: When is a blank not a null or ''  (Sean Davis <sdavis2@mail.nih.gov>)
Список pgsql-general
On Wed, 2005-02-02 at 11:26 +0100, Alban Hertroys wrote:
> mike wrote:
> > I have the following query (I have removed all nulls from the field as
> > test)
> >
> > SELECT first_name,work_email FROM tb_contacts  WHERE
> > tb_contacts.work_email <>'';
> >
> > However I get loads of blank email addresses coming up
> >
> > anyone any ideas
>
> A blank is never a NULL:

I know, I meant visually a blank


>
> SELECT '' IS NULL;
>   ?column?
> ----------
>   f
> (1 row)
>
>
> Try this:
>
> SELECT first_name,work_email FROM tb_contacts  WHERE
> tb_contacts.work_email IS NOT NULL;
>
> Or if there are also blanks among those e-mail addresses:
>
> SELECT first_name,work_email FROM tb_contacts  WHERE
> tb_contacts.work_email IS NOT NULL AND tb_contacts.work_email != '';
>

no difference

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