Oracle Data Integration

Question

I need to remove PL/SQL code and convert that into ODI mapping. I tried using sub query to retrieve NOT EXISTS EVENT_MONTH_WID for EMPLID but now I am kind of stuck at next step on how to make next join with updated last value.

1. The process first checks for missing event_month_wid values in the source table compared to the target table for each employee.

2. Then, it retrieves the last value from the source table before merging new data.

3. After that, the latest value for event_month_wid is updated with the new data.

MERGE INTO wc_emp_tn_Serv_mnth_tmp x
 using (
                WITH mv_ef AS (
                    SELECT 
                        e.person_integration_id AS emplid,
                        e.event_month_wid
                    FROM
                        w_wrkfc_evt_month_f e
                    WHERE
                        NOT EXISTS (
                            SELECT 
                                1
                            FROM
                                wc_emp_tn_serv_mnth_tmp b
                            WHERE
                                    e.event_month_wid = b.event_month_wid
                                AND e.person_integration_id = b.emplid
                        )
                ), lvf_mv AS (
                    SELECT 
                        a.emplid,
                        b.event_month_wid,
                        LAST_VALUE(tn_serv_mnths) OVER(PARTITION BY a.emplid
                            ORDER BY
                                a.event_month_wid
                            RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
                        ) AS last_val_serv_mnths
                    FROM
                        wc_emp_tn_serv_mnth_tmp  a,
                        mv_ef                    b
                    WHERE
                            a.emplid = b.emplid
                        AND a.event_month_wid < b.event_month_wid
                )
                SELECT DISTINCT
                    *
                FROM
                    lvf_mv
            )
y ON ( x.emplid = y.emplid
       AND x.event_month_wid = y.event_month_wid )
WHEN MATCHED THEN UPDATE
SET x.tn_serv_mnths = y.last_val_serv_mnths
WHEN NOT MATCHED THEN
INSERT (
    x.emplid,
    x.event_month_wid,
    x.tn_serv_mnths )
VALUES
    ( y.emplid,
      y.event_month_wid,
      y.last_val_serv_mnths );

I want to convert this code into ODI mapping