Re: How to disable duplicate columns

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От Merlin Moncure
Тема Re: How to disable duplicate columns
Дата
Msg-id b42b73150704091226t1351ad51u85fb5b021c607a54@mail.gmail.com
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Ответ на How to disable duplicate columns  ("Andrus" <kobruleht2@hot.ee>)
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On 4/8/07, Andrus <kobruleht2@hot.ee> wrote:
> I have tables with large number of columns some of which are duplicate.
> I need to use
>
> SELECT t1.*, t2.* FROM t1 join  t2 using (t)
>
> since I don't know all column names of t1 and t2 tables at design time.
>
> In this case PostgreSQL returns table with duplicate columns.
> How to force Postgres to return only first table column  when second table
> contains column with same name?

use can use a natural join:

select * from t1 natural join t2;

this will essentially look for columns that are in both tables, and do
an implicit 'using' on those columns.

be warned, this can lead to surprising behavior -- it only works if
you *want* identically named fields to be part of the join condition,
otherwise the results are undefined.

merlin

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