SELECT network_ind, brand,pc_offer_id, soc, soc_category,  rate
       ,pc_offer_desc, rc_type, 
        avg(total_charges) -- this should be average of 15 days
       ,avg(insufficient_funds_cnt) -- this should be average of 21 days, 
       avg(other_err_cnt) -- this should be average of 21 days, ,
       avg(success_cnt) -- this should be average of 21 days
 FROM cost_drc
 WHERE report_date BETWEEN sysdate-21 AND sysdate-1
 GROUP BY network_ind, brand,pc_offer_id, soc, soc_category, rate, pc_offer_desc, rc_type;

SELECT  network_ind,
        brand,
        pc_offer_id,
        soc,
        soc_category,
        rate,
        pc_offer_desc,
        rc_type, 
        sum(
            case
              when report_date BETWEEN sysdate - 16 AND sysdate - 1 then total_charges
            end
           ) / 15, -- this should be average of 15 days
        sum(insufficient_funds_cnt) / 21, -- this should be average of 21 days, 
        sum(other_err_cnt) / 21, -- this should be average of 21 days
        sum(success_cnt) / 21 -- this should be average of 21 days
  FROM  cost_drc
  WHERE report_date BETWEEN sysdate - 21 AND sysdate - 1
  GROUP BY network_ind,
           brand,
           pc_offer_id,
           soc,
           soc_category,
           rate,
           pc_offer_desc,
           rc_type
/