pgsql-bugs@postgresql.org writes:
> select
> *
> from
> test1 left join test2 on (test1.test1_id = test2.test1_id)
> where
> test1.test1_id = test2.test1_id;
Hm. I think what is happening is that the planner is (mistakenly)
deciding that the where-clause and on-clause are equivalent, and
so dropping the second one ...
regards, tom lane