How to reveal hidden codes

I am not a frequent user of oracle programmer. I remember seeing the solution about four years ago and I can not find from my memory and from the web. I will appreciate if anyone can help. What I have is one varchar2 column containing text records as 'No comment.'. I want to use the DECODE(val, 'No comment.', '', val) to display the empty or other kinds of text. But it won't work. Hence, I used the length function to check on the No comment. value in the column and did return as 11. I remember there was a function I can display the binary code of every character of the data in the field. I also manually checked such value with
SQL>exec :str:='No comment.';
execution successfully

SQL>select DECODE(:str, 'No comment.', '', :str) comments from dual;

I am using 9 R2 on Windows 2K. Thanks.

C Chang Received on Sat Feb 05 2005 - 14:28:38 CST