On 26 June 2014 10:31, David Rowley <dgrowle...@gmail.com> wrote: > If there's no way to tell that the target entry comes from a left join, then > would it be a bit too quirky to just do the NOT NULL checking when > list_length(query->rtable) == 1 ? or maybe even loop over query->rtable and > abort if we find an outer join type? it seems a bit hackish, but perhaps it > would please more people than it would surprise.
We don't know enough about joins at present, so we only allow it when there are no joins (i.e. length == 1). That's just a statement of reality, not a hack. I would agree with Tom that the common usage is to do NOT IN against a table with no where clause, so this would hit the most frequent use case. Maybe Tom will have a flash of insight before commit, or maybe we figure out a way to extend it later. Let's document it and move on. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers