SQL> with test as
  2    (select 233560.66 col from dual union
  3     select 233560.67 from dual union
  4     select 233560.665 from dual
  5    )
  6  select col,
  7    to_char(col, '999G990D00') fmt_1,
  8    trunc(col, 2) fmt_2,
  9    to_char(trunc(col, 2), '999G990D00') fmt_3
 10  from test;

       COL FMT_1            FMT_2 FMT_3
---------- ----------- ---------- -----------
 233560.66  233,560.66  233560.66  233,560.66
233560.665  233,560.67  233560.66  233,560.66
 233560.67  233,560.67  233560.67  233,560.67

SQL>