| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Vik Fearing <vik(dot)fearing(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Join Correlation Name |
| Date: | 2019-10-29 11:05:29 |
| Message-ID: | bd60fa63-99ab-36a8-5b88-58e0a7162052@2ndquadrant.com |
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| Lists: | pgsql-hackers |
On 2019-10-29 11:47, Vik Fearing wrote:
> When joining tables with USING, the listed columns are merged and no
> longer belong to either the left or the right side. That means they can
> no longer be qualified which can often be an inconvenience.
>
>
> SELECT a.x, b.y, z FROM a INNER JOIN b USING (z);
>
>
> The SQL standard provides a workaround for this by allowing an alias on
> the join clause. (<join correlation name> in section 7.10)
>
>
> SELECT j.x, j.y, j.z FROM a INNER JOIN b USING (z) AS j;
>
>
> Attached is a patch (based on 517bf2d910) adding this feature.
Is this the same as https://commitfest.postgresql.org/25/2158/ ?
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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