Select a column from an inner select statement

Question

On my oracle 10g running on solaris, I am running this little query that gives me
the right results (I needed one more column and not able to get to it, hence looking for some ideas here)
Select a.othtype, a.date_from, a.date_to,b.process
from bio_plan_other a,
bio b,
Where a.bkey = b.bkey
and a.date_from <
(Select min(f.edate)
from bio_service f
where f.bkey = a.bkey) ;
In the inner select table bio_service, I have an additional column called service_name. Hence for the min(f.edate), there is a corresponding service_name.
How do I get that service_name in my topmost SELECT statement ?
In other words, I wanted to do something like...
Select a.othtype, a.date_from, a.date_to,b.process,f.service_name
from bio_plan_other a,
bio b,
Where a.bkey = b.bkey
and a.date_from <
(Select min(f.edate)
from bio_service f
where f.bkey = a.bkey) ;
But this gives me,
ORA-00904 : f.service_name : invalid identifier
Thanks

Answer 1

Hi
Not knowing your datamodel, but you probably have more service names per date, so did you try this?
WITH t_bio_service AS (SELECT b2.bkey, b2.min_edate, b.service_name
                         FROM bio_service b
                            , (SELECT MIN(edate) min_edate, bkey
                                 FROM bio_service
                                GROUP BY bkey) b2
                        WHERE b2.bkey = b.bkey
                          AND b2.min_edate = b.edate)
SELECT a.othtype, a.date_from, a.date_to,b.process, t.service_name
  FROM bio_plan_other a,
       bio b,
       t_bio_service t
WHERE a.bkey = b.bkey
   AND t.BKEY = b.bkey
   AND a.date_from < t.min_edateHope this helps.
Regards Auke