Please help me in joining two tables?

Question

Hi ..
I am using oracle 11g.
I  have two  tables with below description
1.esb_v_study_personnel
study_code_alias       varchar2,
site_id                      number ,
role_at_site_level_desc varchar2
2. esb_v_study_site
study_code_alias varchar2
site_id
I am trying to count the role_at_site_level_desc where it is'Field Monitor' or 'Primary Monitor'
so i wrote the below query
select  study_code_alias,site_id,
(role_at_site_lvl_desc) no_of_study_monitors
esb_v_study_site_personnel
study_code_alias IN &arg_trial_code
role_at_site_lvl_desc in ('Field Monitor','Primary Monitor')
group by study_code_alias,study_site_id
order by study_site_id
by using the above i am getting 1617 rows.
but i want map the resultant site_id
esb_v_study_site having 1647 rows. So i want to get all the site_id's  in esb_v_study_site table  by mapping to above query.
Can you guide me on this,
I have tried with left outer join but still iam getting 1617 rows.
select study_code_alias,
(role_at_site_lvl_desc) no_of_study_monitors
esb_v_study_site_personnel
study_code_alias IN &arg_trial_code
role_at_site_lvl_desc in ('Field Monitor','Primary Monitor')
group by study_code_alias,study_site_id
order by study_site_id) a
LEFT OUTER JOIN
ON a.trial_no=d.trial_no and a.study_site_id=d.study_site_id 
where d.study_code_alias in &arg_trial_code
group by d.study_code_alias,d.study_site_id,a.no_of_study_monitors
order by d.study_site_id
Please help me on this???

Answer 1

I'm not quite sure, since your query seems missing some smaller parts. It was probably crumbled during some copy&paste to this forum.
I guess that the reason is either that the left join is done after the group by or that the count on the column will not count NULL values that might be created by the outer join.
Maybe you can start with the following query and give us the results and tell us if it is still wrong and what the expected result would be.
example (not syntax tested)
select  d.study_code_alias
    ,d.site_id
   , count(a.role_at_site_lvl_desc) no_of_study_monitors
   , count(distinct a.role_at_site_lvl_desc) no2
   , count(*) no3
from esb_v_study_site d
left join esb_v_study_site_personnel a on a.trial_no=d.trial_no and a.study_site_id=d.study_site_id and a.role_at_site_lvl_desc in ('Field Monitor','Primary Monitor')
where d.study_code_alias IN (&arg_trial_code)
group by d.study_code_alias,d.study_site_id
order by d.study_site_id;
btw: If you read the FAQ in the upper right corner, there it says how to post good looking sql code.