Re: Join Correlation Name

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.