Retrieving a record that doesn't exist

Question

I know that topic doesn't make sense, but here's what I'm trying to do:
When I run this query: select distinct period_oid from wr_measure_value order by period_oid desc
I get results like this:
5219
5218
5217
5216
Then when i run this query: select wr_measure_value_oid, period_oid, project_associate_oid from wr_measure_value where project_associate_oid = 5 order by period_oid desc
Since no wr_measure_value_oid exist for period_oid 5219, 5218, and 5217 where project_associate_oid=5 none are returned. How would you return rows for these period_oids and project_associate_oid=5? So for example I could have something like this:
wr_measure_value_oid period_oid project_associate_oid
-1 5219 5
-1 5218 5
-1 5217 5
32 (real id) 5216 5

Answer 1

try something like:
with period as (
select distinct period_oid from wr_measure_value
select nvl(a.wr_measure_value_oid, -1), b.period_oid, 5
from period b
left outer join wr_measure_value a
on (a.period_oid = b.period_id
    and a.project_associate_oid = 5)