Inclusion of data based on date

Question

Hello:
I need to extract data for patients who have more than 2 visits to the doctor.
My query is at the end of the post.
The criteria is to include only patients which a trait_date >= 09/01/2006 and have been seen 2 or more times from that date.
For example, Patient A has a date of 12/01/2007 and Patient B has a date of 9/01/2007, 12/12/2007, and 03/01/2008. The query needs to exclude Patient A because they only had one visit whereas Patient B had three visits and it is Patient B that should show up in the data.
I can't seem to figure out how to write the statement that would let me accomplish this.
Can someone help me?
Thank you in advance. Here is the code.
select a.dwkey_patient, a.date_of_birth, TRUNC(months_between(sysdate, a.date_of_birth)/12) AGE,
      b.dwkey_traittype, b.trait_date, b.trait_value
from dd.patient_dim a, search.document_traits b
where a.dwkey_org = b.dwkey_org
and a.dwkey_patient=b.dwkey_patient
and a.dwkey_org=45
and b.dwkey_traittype IN (36883,36885,36884) and b.dwkey_traittype <> 36391
and b.trait_date >= '01-SEP-06'
and (b.trait_value <= '35' or b.trait_value = 'Y')
and TRUNC(months_between(sysdate, a.date_of_birth)/12) >= 18
order by age asc, a.dwkey_patient asc, b.trait_date asc;Edited by: nyc2292 on Nov 7, 2008 12:03 PM

Answer 1

WITH PATIENTS AS (SELECT 1 ID, 'Patient 1' NAME FROM DUAL
                  UNION ALL
                  SELECT 2 ID, 'Patient 2' NAME FROM DUAL
     VISITS   AS (SELECT 1 PATIENT_ID, TO_DATE('01.01.2008', 'DD.MM.YYYY') VISIT_DATE,'Illness' REASON  FROM DUAL
                  UNION ALL
                  SELECT 1 PATIENT_ID, TO_DATE('01.01.2007', 'DD.MM.YYYY') VISIT_DATE, 'Pregnant' REASON FROM DUAL
                  UNION ALL
                  SELECT 2 PATIENT_ID, TO_DATE('01.01.2007', 'DD.MM.YYYY') VISIT_DATE,'Hungry' REASON  FROM DUAL
                  UNION ALL
                  SELECT 2 PATIENT_ID, TO_DATE('01.01.2006', 'DD.MM.YYYY') VISIT_DATE, 'Thirsty' REASON FROM DUAL
SELECT ID,
       NAME,
       REASON
  FROM (
  SELECT ID,
         NAME,
         REASON,
         COUNT(*) OVER (PARTITION BY PATIENT_ID) VISITS
    FROM PATIENTS,
         VISITS
   WHERE ID=PATIENT_ID
     AND VISIT_DATE>TO_DATE('01.09.2006', 'DD.MM.YYYY')
WHERE VISITS>1