2009/3/6 Christian Schröder <cs(at)deriva(dot)de>
> Hi list,
> if I want to find all records from a table that don't have a matching
> record in another table there are at least two ways to do it: Using a left
> outer join or using a subselect. I always thought that the planner would
> create identical plans for both approaches, but actually they are quite
> different which leads to a bad performance in one case.
>
Couldn't you also use: SELECT fk FROM b EXCEPT SELECT id FROM a;