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Inner Join question

From: "Keith Turner" <kturner(at)cloudsystems(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: Inner Join question
Date: 2008-11-07 21:38:06
Message-ID: E15577A9B0DBD9489F41C761934D08C87008AA@cloudfs1.cloudsystems.com (view raw or flat)
Thread:
Lists: pgsql-novice
Should have used reply all - solution works and appreciated and now
posted to group.

K.

Thanks,

Can't do the devices.*, rooms.*, bridge.* as I get the error "column ID
is duplicated" - but explicitly naming the columns and using AS on these
is no big deal

The join worked, which is what I'm really thankful for - wasn't sure
about the syntax of adding a join to a join in that way - that's why
it's a novice list.

Much appreciated,

Keith

-----Original Message-----
From: Michael Swierczek [mailto:mike(dot)swierczek(at)gmail(dot)com] 
Sent: Friday, November 07, 2008 3:23 PM
To: Keith Turner
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: [NOVICE] Inner Join question

Keith,
    The * was a problem because the query analyzer did not know which
table to grab all columns from.   If you want all columns from more
than one table, you have to do alias.* for each one.   In this case,
you want:
select devices.*, rooms.*, bridge.* from ....

If you want devices to always be listed, even with no bridge entries,
you would do a left join to guarantee all rows from the first table
are included.

I think this is what you want:
SELECT devices.*, rooms.*, bridge.*
FROM devices
LEFT JOIN bridge on bridge.deviceid=devices.id
LEFT JOIN room on bridge.roomid = rooms.id;

-Mike


On Fri, Nov 7, 2008 at 3:45 PM, Keith Turner <kturner(at)cloudsystems(dot)com>
wrote:
> Hi,
>
> I have three tables
>
> 1) A list of devices
> 2) List of rooms
> 3) A bridge table that relates the two using each table's ID column
>
> Any device can be in 0 to All rooms
>
> I want to create a view that joins both tables that in includes all
> columns from all 3 tables.
>
> I'm not sure how to link joins in the Postgres SQL syntax. I'm more
used
> to the =* one.
>
> I want to do something like
>
> SELECT (explicit list of all tables columns - didn't like * but was ok
> with actual list)
> FROM
> devices,rooms,bridge
> WHERE
> bridgeroomid = rooms.id
> AND
> bridgedeviceid=*devices.id
>
> so that devices with no associated rooms would have null values for
> those columns but be listed.
>
> Any advice appreciated.
>
> KDT
>
> --
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> To make changes to your subscription:
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>

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Next:From: gcjDate: 2008-11-11 15:23:38
Subject: Automating Postgres Backup
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Subject: Re: Inner Join question

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