oracle like 变量

create or replace function GET_COUNT_ZS
(deptcode  in varchar2, tablename in varchar2,bs in varchar2)
return  varchar2
is
num varchar2(1000);
c number;
begin
if(bs=0) then
num:='select count(*) from '||tablename||' where  deptcode like '''||deptcode||'%''';
end if;
if(bs=1) then
num:='select count(*) from '||tablename||' where  deptcode like '''||deptcode||'%'''||' and  SFDTGL=1' ;
end if;
execute immediate num into   c;
return c;
end;