Mischa <mischa.Sandberg@telus.net> writes:
> Quoting Tom Lane <tgl@sss.pgh.pa.us>:
>> WHERE a.x > b.y AND a.x < 42
> Out of curiosity, will the planner induce "b.y < 42" out of this?
No. There's some smarts about transitive equality, but none about
transitive inequalities. Offhand I'm not sure if it'd be useful to add
such. The transitive-equality code pulls its weight because you so
often have situations like
create view v as select a.x, ... from a join b on (a.x = b.y);
select * from v where x = 42;
but I'm less able to think of common use-cases for transitive
inequality ...
regards, tom lane