Date1 = from_date

LOOP while date1 < to_date_parm /* you will have to correct this lose logic */
  stmt := stmt ||
          ', sum( decode( to_char(c.dcn_date, ''yyyymon''), ''' ||
  /* now we have to build the format */
  to_char(date1,'yyyymon') || /* gives 2005jan */
  ''', c.dcn_brokerage_amt, 0 ) ) ' ||
  /* now we want the month as a label */
  to_char(date1,'MON'); /* gives JANUARY */
 
  /* increment month */
  add_months(date1, 1);
END LOOP

stmt := stmt ||
"FROM dtm_contract_note_master c, dtm_contract_note_details d
WHERE c.dcn_date BETWEEN :FROMDATE AND :TODATE
AND (SUBSTR(c.dcn_ent_ctrl_id,1,4)||'00000000') = :BRANCHID
and c.dcn_no=d.dcd_dcn_no
and SUBSTR(d.dcd_dcm_id,1,3)=NVL(:TTYPE,SUBSTR(d.dcd_dcm_id,1,3))

GROUP BY (SUBSTR(c.dcn_ent_ctrl_id,1,4)||'00000000') )
ORDER BY 1" /* you will have to add the concat pair for each line */

/* Now parse and execute the 'stmt' */