Re: BUG #17408: Duplicate aliases silently fail

On Wed, Feb 16, 2022 at 10:46 AM PG Bug reporting form
<noreply@postgresql.org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference:      17408
> Logged by:          Kevin Potgieter
> Email address:      porturpotgieter@gmail.com
> PostgreSQL version: 13.6
> Operating system:   Not related
> Description:
>
> Hi,
>
> Assigning aliases to columns works perfectly.
>
> eg. "SELECT name AS customer_name FROM customers"
>
> However you are able to assign duplicate aliases which does not cause a
> conflict
>
> eg. "SELECT name AS customer_name, surname AS customer_name FROM
> customers"
>
> The expectation here is that duplicate aliases would cause the query to fail
> due to duplicate column names in the result, however there is no error or
> warning.

This may look weird but the SQL standard allows it. Postgres is only
following what the standard dictates.

Best regards,
Pantelis Theodosiou

>
> Regards
> Kevin
>