From: Jerry Sievers <jerry@jerrysievers.com>
To: pgsql-general@postgresql.org
Subject: Re: A Not Join
Date: 01 Nov 2005 21:28:22 -0500
Message-ID: <m34q6v7ph5.fsf@prod01.jerrysievers.com> (raw)
References: <43677B35.6010005@lani.co.za>
L van der Walt <mailing@lani.co.za> writes:
> I have three table:
> Users - Contains username, ID etc...
> Permissions - A permission name and ID
> Link up table - The user.id and permission.id
>
> If a user.id and a permission.id row exists in the linkuptable the user
> have that permission granted.
>
> With the statement below I can see the permissions a user have.
>
> SELECT users.username, permissions.name
> FROM users INNER JOIN linkuptable
> ON (users.id = linkuptable.userid)
> INNER JOIN permissions
> ON (permissions.id = linkuptable.permissionid)
> WHERE users.username = 'DummyUser'
>
> How do I see the permissions that user DON'T have with a fast SQL statement.
>
Simple.
select permname
from permissions
where permid not in (
select permid
from linkage
where userid = 'dummy'
);
Or... a slick way to get the anti-permission for the whole bunch of
users is to;
cross join the userids with permids and then EXCEPT SELECT from
linkage table to filter out the active permissions.
Have fun!
--
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Jerry Sievers 305 854-3001 (home) WWW ECommerce Consultant
305 321-1144 (mobile http://www.JerrySievers.com/
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To: pgsql-sql@postgresql.org
Cc: jerry@jerrysievers.com, pgsql-general@postgresql.org
Subject: Re: A Not Join
In-Reply-To: <m34q6v7ph5.fsf@prod01.jerrysievers.com>
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