select b.member_id, b.cell_id, c.mail_start_date, 'O' as event_type
from 
(select member_id, eo.cell_id
 from ftd.event_opened eo
 where nvl(eo.seedlist_ind,0)=0
 and eo.modified_on >= to_date('10-09-2011 00:00:00','mm-dd-yyyy hh24:mi:ss')
 and eo.modified_on < to_date('10-10-2011 00:00:00','mm-dd-yyyy hh24:mi:ss')
 group by member_id, eo.cell_id
) a,
ftd.event_opened b, ftd.cells c
where b.member_id = a.member_id and b.cell_id = a.cell_id
and b.cell_id=c.cell_id 
and nvl (b.seedlist_ind, 0) = 0
and c.mail_start_date >= to_date('10/01/2010','mm/dd/yyyy')
group by b.member_id, b.cell_id, c.mail_start_date
having min (b.modified_on) >= to_date('10-09-2011 00:00:00','mm-dd-yyyy hh24:mi:ss')
and min (b.modified_on) < to_date('10-10-2011 00:00:00','mm-dd-yyyy hh24:mi:ss')

where 1=2