Convert rows into a single column

Question

create table suresh
id number,
ch char(1)
insert into suresh values(1,'i');
insert into suresh values(1,'a');
insert into suresh values(1,'m');
insert into suresh values(1,'b');
insert into suresh values(1,'o');
insert into suresh values(1,'y');
select * from suresh
     id     ch
     1     i
     1     a
     1     m
     1     b
     1     o
     1     y
I am looking for output somethign like this
id ch
1 iamboy
..

Answer 1

Not for that data, no. You have a set of characters with no information about 'order', so they could appear in any order.
If you had some numbering against them, you could pivot the data and concatenate them, but in truth even the concatenation symbol "||" is a built in function, as well as the functions needed to pivot it...
SQL> ed
Wrote file afiedt.buf
  1  with t as (select 1 as id, 'i' as ch from dual union all
  2             select 2, 'a' from dual union all
  3             select 3, 'm' from dual union all
  4             select 4, 'b' from dual union all
  5             select 5, 'o' from dual union all
  6             select 6, 'y' from dual)
  7  --
  8  select max(decode(id,1,ch))||max(decode(id,2,ch))||max(decode(id,3,ch))||max(decode(id,4,ch))||max(decode(id,5,ch))||max(decode(id,6,ch))
  9* from t
SQL> /
MAX(DE
iamboy
SQL>Whatever you do, there's going to be some built in functions somewhere.
Unless.... you do something horrendous like...
SQL> ed
Wrote file afiedt.buf
  1  with t as (select 1 as id, 'i' as ch from dual union all
  2             select 2, 'a' from dual union all
  3             select 3, 'm' from dual union all
  4             select 4, 'b' from dual union all
  5             select 5, 'o' from dual union all
  6             select 6, 'y' from dual)
  7  --
  8  select (select ch from t where id = 1)||
  9         (select ch from t where id = 2)||
10         (select ch from t where id = 3)||
11         (select ch from t where id = 4)||
12         (select ch from t where id = 5)||
13         (select ch from t where id = 6)
14* from dual
SQL> /
(SELEC
iamboy