Re: CTE or Subselect and outer joins not behaving as expected?

In article <A3B9626E-9093-4E7C-9986-BA6597665F3C(at)bepress(dot)com>,
Joel Stevenson <jstevenson(at)bepress(dot)com> writes:

> select tally_table. tally_mon, met.datum
> from (
> select distinct date_trunc( 'month', '2011-06-01'::date + tally_day )::date as tally_mon
> from generate_series( 0, ( select current_date - '2011-06-01'::date ) ) as tally_day
> ) as tally_table full outer join my_existing_table as met on( tally_mon = met.month )
> where met.series = 1;
> -- ** See SETUP below **

> This produces rows only for those that exist in my_existing_table and no left join output which I'd expect for the rest of the tally_table rows.

Your WHERE clause turns the OUTER into an INNER JOIN. Try

select tally_table.tally_mon, met.datum
from (
select distinct date_trunc( 'month', '2011-06-01'::date + tally_day )::date as tally_mon
from generate_series( 0, ( select current_date - '2011-06-01'::date ) ) as tally_day
) as tally_table
left join my_existing_table as met on tally_mon = met.month and met.series = 1;