Re: IN clause
От | Marcus Engene |
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Тема | Re: IN clause |
Дата | |
Msg-id | 45670A16.9040508@engene.se обсуждение исходный текст |
Ответ на | Re: IN clause ("Brandon Aiken" <BAiken@winemantech.com>) |
Ответы |
Re: IN clause
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Список | pgsql-general |
I see we have a C J Date fan on the list! ;-) There is one other case where I personally find nullable columns a good thing: process_me ish flags. When a row is not supposed to be processed that field is null and when a field is null it wont be in the index [at least on Oracle]. Best regards, Marcus Brandon Aiken skrev: > Hasn't it been said enough? Don't allow NULLs in your database. > Databases are for storing data, not a lack of it. The only time NULL > should appear is during outer joins. > > -- > Brandon Aiken > CS/IT Systems Engineer > -----Original Message----- > From: pgsql-general-owner@postgresql.org > [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Martijn van > Oosterhout > Sent: Friday, November 24, 2006 7:20 AM > To: surabhi.ahuja > Cc: A. Kretschmer; pgsql-general@postgresql.org > Subject: Re: [GENERAL] IN clause > > On Fri, Nov 24, 2006 at 05:31:07PM +0530, surabhi.ahuja wrote: >> That is fine >> but what I was actually expecting is this >> if >> select * from table where col_name in (null, 'a', 'b'); >> >> to return those rows where col_name is null or if it = a or if it is = > b >> >> But i think in does not not support null queries , am i right? > > You'll need to check the standard, but IN() treats NULL specially, I > think it returns NULL if any of the elements is null, or something like > that. It certainly doesn't work the way you think it does. > > Have a nice day,
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