Setting Criteria on a COUNT variable

Question

Hello:
I have a query where I am counting the number of visits per patient. I need to extract only those patients who have more than 2 visits. When I attempt to set my condition based on my COUNT function, I'm receiving the following error message:
ORA-00904:VISITS invalid identifier
I tried placing my condition in a number of places and I'm still receiving the same error message. I made three different attempts to with the condition statement.
The query that I currently have without the visits condition is the following (I commented out the VISITS criteria):
SELECT A.DWKEY_PATIENT, COUNT(A.TRAIT_DATE) VISITS
FROM HELEN.DOCUMENT_TRAITS A, HELEN.PATIENT_DIM B
WHERE A.ID=B.ID
      AND A.DWKEY_PATIENT=B.DWKEY_PATIENT
      AND B.DWKEY_ORG = 45
      AND TRUNC(MONTHS_BETWEEN(SYSDATE,B.DATE_OF_BIRTH)/12) >=18
      AND A.TRAIT_DATE >= '01-SEP-06'
      AND (A.TRAIT_VALUE <= '35' OR A.TRAIT_VALUE = 'Y')
      AND  A.DWKEY_TRAITTYPE IN (36883,36884,36885)
*--and visits > 1 (attempt #1)* 
AND NOT EXISTS (SELECT 1
                FROM HELEN.DOCUMENT_TRAITS B
                WHERE B.DWKEY_PATIENT = A.DWKEY_PATIENT
                AND B.DWKEY_TRAITTYPE = 36391)
*--and visits > 1 (attempt #2)*
GROUP BY A.DWKEY_PATIENT
*--HAVING VISITS > 1 (attempt #3)*The result this query produces looks like this:
ID   DWKEY_PATIENT    VISITS
1    45454545          1
2    23232323          1
*3    12121212          2*  ((this is the only record that should appear after adding VISITS > 1)) Once I include the condition of VISITS > 1 the result of the query should only display record #3: dwkey_patient 12121212 with 2 visits. Records 1 and 2 should disappear.
I cannot seem to figure out where to place my VISITS > 1 in my query to produce the desired result.
My second issue with the query is to include the following fields from the tables:
dwkey_patient from patient_dim table,
date_of_birth from patient_dim table,
age calculation,
dwkey_traittype from document_traits table,
trait_date from document_traits table,
trait_value from document_traits table
When I try to include these columns in my SELECT statement, I receive a message stating: not a group by expression.
This is where I'm trying to place the additional columns:
SELECT A.DWKEY_PATIENT, COUNT(A.TRAIT_DATE) VISITS, b.date_of_birthCan someone help me out?
Thank you.
Edited by: hbradshaw310 on Nov 9, 2008 3:21 PM

Answer 1

And yes, your attempt #3 is the right one assuming you just need just patient. And since you need non-aggregated data, use:
SELECT  DWKEY_PATIENT,
        VISITS,
        date_of_birth
  FROM  (
         SELECT  A.DWKEY_PATIENT,
                 COUNT(A.TRAIT_DATE) OVER(PARTITION BY A.DWKEY_PATIENT) VISITS,
                 b.date_of_birth
           FROM  HELEN.DOCUMENT_TRAITS A,
                 HELEN.PATIENT_DIM B
           WHERE A.ID=B.ID
             AND A.DWKEY_PATIENT=B.DWKEY_PATIENT
             AND B.DWKEY_ORG = 45
             AND TRUNC(MONTHS_BETWEEN(SYSDATE,B.DATE_OF_BIRTH)/12) >=18
             AND A.TRAIT_DATE >= '01-SEP-06'
             AND (A.TRAIT_VALUE <= '35' OR A.TRAIT_VALUE = 'Y')
             AND  A.DWKEY_TRAITTYPE IN (36883,36884,36885)
  WHERE VISITS > 1
/SY.