SQL Server 2008 - select based on query results - sql-server-2008

Question

I am currently working with this query
SELECT DISTINCT
se.src_aet AS "Ripped By",
CONVERT(varchar(32), s.created_time, 113) AS "Date/Time Sent",
p.pat_name AS "Patient Name",
p.pat_id AS "Patient ID",
s.accession_no AS "ACC #",
p.pat_birthdate AS "DOB",
s.mods_in_study AS "MOD",
CONVERT(varchar(32), s.study_datetime, 113) AS "Study Date",
s.study_desc AS "Study Desc",
s.study_custom1 AS "Inst Name"
FROM
dbo.patient AS p
INNER JOIN
dbo.study AS s ON s.patient_fk = p.pk
INNER JOIN
dbo.series AS se ON se.study_fk = s.pk
WHERE
accession_no like '%OUT%'
AND s.created_time >= CAST(getdate() as DATE)
AND s.created_time < CAST(DATEADD(day, 1, getdate()) as DATE)
ORDER BY
"Date/Time Sent" DESC
In the above example, it comes back with:
RIPPED BY DATE/TIME SENT PATIENT NAME PATIENT ID ACC# DOB
BC 18 Aug 2014 12:58:44:297 DOE^JOHN^^^ HOSP1234 OUT 19510101
I have taken the last few columns away (in the above example output) for simplicity sake here.
It is working correctly. It comes back with a list of studies that have the word 'OUT' in the accession_no column and that have been written to the DB 'today'.
What I am wanting to return are all of the unique values for 'pat_id' in the dbo.patient table for those found in the query. Some of those patients found the query above might already exist in the dbo.patient table if they have been to our site before, but they will have a different 'pat_id'.
What I want the output to look like is:
RIPPED BY DATE/TIME SENT PATIENT NAME PATIENT ID_OUT PATIENT ID_EXIST ACC# DOB STUDY DATE STUDY DESC INST NAME
the column 'PATIENT ID_OUT' is the patient ID that would be on the study that has the value of 'OUT' in the accession_no column and the column 'PATIENT ID_EXIST' is the existing patient ID, if it does exist. The value for 'PATIENT ID_EXIST' may be blank in some cases if the patient is new.
I was thinking I was needing to do a sub-query here, but maybe that is not the right thing to do in this case? Correct me if I am wrong.
EDIT: I have provided an example of the output. I am trying to figure out if the patient in the output has a different 'Patient ID' based on searching for the pat_name and pat_dob in the query results. If there is another or more than one patient ID in the pat_id column, then I would like them in the output.
I hope this is clear :)

Answer 1

I usually tackle tasks like this by treating the query as a table and joining to it.
SELECT p.*
FROM dbo.patient p
INNER JOIN (your big query) q
ON q.pat_id = p.pat_id