SQL & PL/SQL

Hello Folks,
I have this procedure which actually has a MERGE command inside the procedure and basically all it does is it inserts all the data from the temp table when there is no match on the Bill_ID.
Here my requirement is on a daily basis the Bill_ID can be assigned to a different Event_ID. If for example the Bill_ID has changed its event tommorrow the procedure should update the row with the new Event_ID. But in my procedure its not updating because the Bill_ID hasnt changed and its the same(coz am using MERGE insert when not matched). How do i acheive this on a day to day basis. What is the building block of code to do this. Am kinda new to programming and am trying to learn.

CREATE OR REPLACE PROCEDURE load_fadm_staging_area_test (
  p_data_load_date DATE
) IS
  v_start_date   DATE;
  v_end_date     DATE;
BEGIN
  SELECT NVL (p_data_load_date, SYSDATE) - 7,
         NVL (p_data_load_date, SYSDATE) - 1
  INTO   v_start_date,
         v_end_date
  FROM   DUAL;
 
  MERGE INTO stg_fadm_hri_stage_bill_test b
  USING      (SELECT *
              FROM   stage_bill
              WHERE  created_date BETWEEN v_start_date AND v_end_date) a
  ON         (b.bill_id = a.bill_id,)
  WHEN NOT MATCHED THEN
    INSERT     (batch_id,
                beginning_service_date,
                bill_id,
                bill_method,
                bill_number,
                bill_received_date,
                bill_status,
                bill_type,
                change_oltp_by,
                change_oltp_date,
                client_datafeed_code,
                client_id,
                created_date,
                date_of_incident,
                date_paid,
                deleted_oltp_by,
                deleted_oltp_date,
                duplicate_bill,
                ending_service_date,
                event_case_id,
                event_id,
                from_oltp_by,
                oltp_bill_status,
                review_status,
                row_effective_date,
                row_end_date
               )
    VALUES     (a.batch_id,
                a.beginning_service_date,
                a.bill_id,
                a.bill_method,
                a.bill_number,
                a.bill_received_date,
                a.bill_status,
                a.bill_type,
                a.change_oltp_by,
                a.change_oltp_date,
                a.client_datafeed_code,
                a.client_id,
                a.created_date,
                a.date_of_incident,
                a.date_paid,
                a.deleted_oltp_by,
                a.deleted_oltp_date,
                a.duplicate_bill,
                a.ending_service_date,
                a.event_case_id,
                a.event_id,
                a.from_oltp_by,
                a.oltp_bill_status,
                a.review_status,
                v_start_date,
                v_end_date
               );
END load_fadm_staging_area_test;

Edited by: user11961230 on Jan 26, 2011 9:36 AM