Re: UPDATE using sub selects

Hi,

On 3/16/07, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> NikhilS <nikkhils(at)gmail(dot)com> writes:
> > To allow both of the above to hold, I think the subselect will have to
> be
> > treated like a EXPR_SUBLINK subquery. I was wondering if we have a
> similar
> > mechanism for plain selects/subselects to check and restrict their
> output to
> > a single row.
>
> No. Offhand I think you'd either need to relax EXPR_SUBLINK to allow
> multiple output columns, or invent a ROW_SUBLINK SubLinkType that is
> just like EXPR_SUBLINK except for allowing multiple output columns.
> The latter would probably be less likely to break other things...

Yeah, was looking at EXPR_SUBLINK and its single column use case and drove
to the same conclusion that inventing a new sublink type would be better
too. It is indeed becoming a "not so simple and narrow fix" as you had
mentioned earlier in your first response :)

Regards,
Nikhils
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