Remove whitespaces/blanks from a string

[jmodic]

I'm affraid you'll have to use PL/SQL for that. Something like the following function:

SQL> create or replace function remove_blanks_after_comma (p_in in varchar2)
  2  return varchar2 as
  3    v_out varchar2(4000) := p_in;
  4  begin
  5    while INSTR(v_out, ', ') > 0 loop
  6      v_out := replace(v_out, ', ', ',');        
  7    end loop;
  8    return v_out; 
  9  end;
 10  /

Function created.

SQL> SELECT remove_blanks_after_comma('Tom,   Hanks') FROM dual;

REMOVE_BLANKS_AFTER_COMMA('TOM,HANKS')
--------------------------------------------------------------------------------
Tom,Hanks

SQL> SELECT remove_blanks_after_comma('Tom    Hanks') FROM dual;

REMOVE_BLANKS_AFTER_COMMA('TOMHANKS')
--------------------------------------------------------------------------------
Tom    Hanks

SQL>