Bonjour Vik,
> Is quoting the spec good enough?
> SQL:2016 Part 2 Foundation Section 7.10 <joined table>:
Ah, this is the one information I did not have when reviewing Peter's
patch.
> <named columns join> ::=
> USING <left paren> <join column list> <right paren> [ AS <join correlation name> ]
>
> <join correlation name> ::=
> <correlation name>
>
> I think possibly what the spec says (and that neither my patch nor
> Peter's implements) is assigning the alias just to the <join column
> list>.
I think you are right, the alias is only on the identical columns.
It solves the issue I raised about inaccessible attributes, and explains
why it is only available with USING and no other join variants.
> So my original example query should actually be:
>
> SELECT a.x, b.y, j.z FROM a INNER JOIN b USING (z) AS j;
Yep, only z should be in j, it is really just about the USING clause.
--
Fabien.