From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Ryan Murphy <ryanfmurphy(at)gmail(dot)com>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: postgres question: Views with duplicate field names |
Date: | 2016-09-05 20:06:29 |
Message-ID: | f976b88f-740b-0bac-c462-d65195589a5f@aklaver.com |
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Lists: | pgsql-general |
On 09/05/2016 12:55 PM, Ryan Murphy wrote:
> Hello, I have a question about views in Postgres.
>
> Given a table like so:
>
> create table todo (
> id serial,
> task text,
> done_time timestamp default null
> );
>
> it is legal (though perhaps not advised, by some) to query it like so:
>
> select task, * from todo;
>
> This gives a result with 2 redundant "task" fields (with duplicate names):
>
> task | id | task | done_time
> --------------+----+--------------+-----------
> wash the dog | 1 | wash the dog |
>
> However, if I try to make a view of this I hit a problem: views can't
> have duplicate field names:
>
> create view task2 as select task, * from todo;
>
> ERROR: column "task" specified more than once
>
> I understand this may seem like a silly thing to want to do, but my
> question is if there is an easy way to automatically de-dup the columns
> of the query so I can create a view from it. Or is there any
> fundamental reason why views can't be allowed to have duplicate columns,
> just like the result set above?
test=> create view task2 as select task AS task_1 , * from todo;
CREATE VIEW
test=> \d task2
View "public.task2"
Column | Type | Modifiers
-----------+-----------------------------+-----------
task_1 | text |
id | integer |
task | text |
done_time | timestamp without time zone |
>
> Thanks!
>
> Ryan
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
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