Re: Postgresql sql query - selecting rows outside a join

On Dec 1, 2003, at 10:15 AM, Graham Leggett wrote:

> Hi all,
>
> I am trying to do a query that returns all rows that are _not_ part of
> a join, and so far I cannot seem to find a query that doesn't take 30
> minutes or more to run.
>
> The basic query is "select * from tableA where tableA_id NOT IN (select
> tableA_id from tableB)".
>
> Is there a more efficient way of doing this?
>
> Regards,
> Graham
> --
>
This should be more efficient:

select * from tableA where not exists (select null from tableB where
tableA_id = tableA.tableA_id);

Version 7.4 fixes the slow IN - NOT IN, but I haven't tested it myself
yet to see how it compares to this.

Adam Ruth