如何样写函数

Create function f_get_knit_time(dept_id in varchar2,process_id in varchar2,beginDt in varchar2,endDt in varchar2)return integer is result;begin       select nvl( sum(QUANTITY * knit_time)/60,0) as knit_time                        from WORK_CKM_KNITTIME a,(SELECT                                WSM.LOT_NO,                                WBM.CARD_SIZE,                                count(*) QUANTITY                                        from    WORKSCAN_SH_LIST WSL,                                WORKSCAN_SH_MAIN WSM,                                   WORK_BAR_LIST WBL,                                WORK_BAR_MAIN WBM,                                work_staff ws,                                work_process wp                        WHERE WSM.PKEY = WSL.PKEY and                                  WBM.CARD_ID=WBL.CARD_ID AND                                WSL.BAR_CODE=WBL.BAR_CODE and                                ws.station_name ='电脑织机' and                                wsm.object_id = ws.staff_id and                        wsm.main_process = wp.process_id  and ws.Dept_ID := dept_id and ws.process_id := process_id and WSM.scan_date >= to_date(''+beginDt+'','dd-MM-yyyy HH24:MI:SS') and WSM.scan_date <= to_date(''+endDt+''+ ' 23:59:59' ,'dd-MM-yyyy HH24:MI:SS')                         GROUP BY WSM.LOT_NO,WBM.CARD_SIZE ) b where a.LOT_NO = b.LOT_NO and a.size_name = b.CARD_SIZEendselect f_get_knit_time('16','+3','18-08-2011','18-08-2011') from dual;请帮我看看这个函数再使用参数和调用函数是不是这样写.

-- 给个列子给你：-- Oracle返回表值的函数create or replace type empobj as object( empno number(4),  ename varchar2(10),  sal   number(7,2))/create or replace type emptb is table of empobj/create or replace function myemp(i_deptno number) return emptbis  Result emptb := emptb();begin  result := emptb();  for i in (select empno, ename, sal from emp where deptno=i_deptno )  loop    result.extend;    result(result.count):=empobj(NULL,NULL,NULL);    result(result.count).empno := i.empno;    result(result.count).ename := i.ename;    result(result.count).sal := i.sal;  end loop;  return(result);end;/  select * from table(myemp(30));