oracle 怎样实现合并相同行 希望是 一条语句

Question

oracle 怎样实现合并相同行 希望是一条语句
如
create table tb
(
  id number,  
  name varchar2(100)
);
insert into tb values(1,'aa');
insert into tb values(2,'bb');
insert into tb values(3,'cc');
insert into tb values(1,'dd');
insert into tb values(1,'ee');实现 
1    aa,dd,ee
2    bb
3    cc    

Answer 1

create or replace function t_f                                                                    
(                                                                               
  v_id number                                                                   
)                                                                               
return varchar2                                                                 
is                                                                              
  result varchar2(5000);                                                        
begin                                                                           
 result := '';                                                                  
 for x in (select name from tb where id = v_id)                                 
 loop                                                                           
     result := result || x.name || ',';                                         
 end loop;                                                                       result := substr(result, 1, length(result) - 1);                               
 return result;                                                                 
end t_f;              
select  id, t_f(id) as name from (select distinct id from tb) x