Re: TODO item

Andrew Gierth wrote:
> >>>>> "Bruce" == Bruce Momjian <bruce(at)momjian(dot)us> writes:
>
> >> 1) select ... from foo, unnest(foo.bar); -- UNNEST is implicitly LATERAL
> [...]
> >> It's point (1) that's the killer - without it, unnest() is just a
> >> trivial shorthand for stuff that can be done anyway; it doesn't
> >> actually add any functionality.
>
> Bruce> OK, so what should the TODO wording be?
>
> Under "SQL Commands":
>
> * implement LATERAL (and corresponding UNNEST functionality)
>
> (LATERAL is, I suspect, a fairly big project because of the amount of
> planner work involved, but it's also a fairly high-value project
> because (a) it's useful (we usually get a couple of cases every week
> on the IRC chan where people ask "how do I do X", where X would be
> trivial with LATERAL but requires complex and often inefficient SQL
> without it), and (b) it potentially presents optimization
> opportunities even for queries that don't use it.)

Added to TODO:

Support LATERAL subqueries

Lateral subqueries can reference columns of tables defined outside
the subquery at the same level. For example, a LATERAL subquery in a
FROM clause could reference tables defined in the same FROM clause.
Currently only the columns of tables defined above subqueries are
recognized.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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