Sql tuning using rank function

Question

Hi,
Can someone help me in writing the below qry using rank() function?
DELETE FROM stc_calllog_ext a
WHERE a.stc_save_status = 'CT'
AND ROWID IN (SELECT a.ROWID
FROM stc_calllog_ext a, calllog_ext b
WHERE a.prod_line_code= b.prod_line_code
AND a.brand_code = b.brand_code
AND a.model_number = b.model_number
AND a.stc_save_status != b.stc_save_status
AND trunc(a.stc_start_time) = trunc(b.stc_start_time)
AND a.stc_start_time BETWEEN TRUNC(SYSDATE-8) AND TRUNC(SYSDATE)
AND a.call_taker_userid = b.call_taker_userid
AND a.cons_telephone_no =b.cons_telephone_no
)

Answer 1

With the information you have provided, I've come up with the following.
SELECT A.ACCOUNT_NO, A.PAYMENT_TYPE, A.INSTALLMENT_TYPE, A.DATE_CHANGE
FROM
    (SELECT account_no, payment_type, installment_type, date_change,
            LEAD( (payment_type), 1)
                 over (partition by account_no order by account_no, DATE_CHANGE)  LEAD_PAY,
            LEAD( (installment_type), 1)
                 over (partition by account_no order by account_no, DATE_CHANGE)  LEAD_INST
      from T_ACCNTS ) A
WHERE A.PAYMENT_TYPE <> NVL(A.LEAD_PAY,99)
   OR A.INSTALLMENT_TYPE <> NVL(A.LEAD_INST,99)
ORDER BY 1, 4;