Re: Query from two tables return error

On 04/01/2016 06:52 AM, arnaud gaboury wrote:
>
>
> On Fri, Apr 1, 2016 at 3:33 PM, Sándor Daku <daku.sandor@gmail.com


>
>     One of many difficulties with computers that they do what you say
>     them to do, not what you think or you think you are saying. :)
>     Lets see:
>     SELECT d.home_dir
>     FROM email.mail_dir d, email.mailusers u  <- make a join between
>     mail_dir and mailusers = join every(!) record from the first table
>     with every(!) record from the second table
>     WHERE u.username='arnaud.gaboury'; <- but I need only those from the
>     joined records where the username is arnaud.gaboury
>
>     And there, you have it.
>
>     You can simply redefine the view.
>
>       SELECT *,((mailusers.domain_name || '/'::text) ||
>     mailusers.username) || '/'::text AS home_dir
>         FROM email.mailusers;
>
>
> Thank you so much. This way I get all needed info in one view.

This might help understand what is going on:

http://www.postgresql.org/docs/9.5/interactive/tutorial-join.html

>
>
>     Notice the * after the SELECT statement.
>     So you have all the data plus the homedir.
>
>     You can leave out the whole view thing and incorporate the home_dir
>     expression right into your select.
>     Or you can write a function which makes this to you with the usename
>     as argument.
>
>     Regards,
>     Sándor
>
>
>
>
>
> --
>
> google.com/+arnaudgabourygabx
>
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>


--
Adrian Klaver
adrian.klaver@aklaver.com