Conditional SQL ( Want to avoid having to write a PL/SQL block )

Question

I have a SQL statement and I was hoping to not have to write an IF-THEN-ELSE condition. Here is the SQL in hand which I need to expand.
I need to list the personal information including address of all the employees. However, in the event that I encounter any address ( Home or Office ) where my State is *"NY"*, I should not list the "NY" Address but instead list the address where my address_location = 'O' and address_state_code = *"CA"*.
Here is my code below. Now, the DB procedure call could retrieve the latest address id as a "NY" location and hence my question.
SELECT '"'||emp.employee_name,
              ||'","'||TO_CHAR(emp.birth_date,'YYYY/MM/DD')
              ||'","'||emp.gender
              ||'","'||RTRIM(ead.address_line1)
              ||'","'||RTRIM(ead.address_line2)
              ||'","'||RTRIM(ead.address_line3)
              ||'","'||RTRIM(ead.address_location) -- 'O': Office; 'H': Home
              ||'","'||RTRIM(ead.adh_city)
              ||'","'||ead.address_zip_code
              ||'","'||ead.address_state_code
FROM    employee             emp,
            employee_address ead
WHERE  emp.emp_num = ead.emp_num
-- The proccedure db_get_address_id returns me the most recent Address with Max Effective Date
AND      ead.address_id = db_get_address_id( emp.emp_num )
ORDER BY v.effective_date DESC, emp.employee_name ASC;
{code}
Thanks in advance !                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

SELECT  emp_address
  FROM  (
         SELECT  '"'||emp.employee_name,
                        ||'","'||TO_CHAR(emp.birth_date,'YYYY/MM/DD')
                        ||'","'||emp.gender
                        ||'","'||RTRIM(ead.address_line1)
                        ||'","'||RTRIM(ead.address_line2)
                        ||'","'||RTRIM(ead.address_line3)
                        ||'","'||RTRIM(ead.address_location) -- 'O': Office; 'H': Home
                        ||'","'||RTRIM(ead.adh_city)
                        ||'","'||ead.address_zip_code
                        ||'","'||ead.address_state_code emp_address,
                        ROW_NUMBER() OVER(ORDER BY v.effective_date DESC, emp.employee_name ASC) RN,
                        CASE
                          WHEN ead.address_state_code = 'NY' THEN CASE MAX(
                                                                           CASE ead.address_state_code
                                                                             WHEN 'CA' THEN 1
                                                                           END
                                                                          ) OVER(PARTITION BY emp.emp_num)
                                                                    WHEN 1 THEN 0
                                                                    ELSE 1
                                                                  END
                          ELSE 1
                        END TAKE_IT -- 0 means it is NY address for employee who also has CA address, 1 otherwise.
           FROM  employee emp,
                 employee_address ead
           WHERE emp.emp_num = ead.emp_num
             -- The proccedure db_get_address_id returns me the most recent Address with Max Effective Date
             AND ead.address_id = db_get_address_id(emp.emp_num)
  WHERE TAKE_IT = 1
  ORDER BY RN
{code}
SY.
Edited by: Solomon Yakobson on Aug 13, 2009 1:38 PM