SQL & PL/SQL :: Number Of Occurrence

I'm trying to find a way to see if a value occurs more than once in a string. I just need to know "T/F", or "Y/N", etc.

The string will be comma delimited.

String: '1,2,3,1'
Ans: "T"

String: '1,2,3,4'
Ans: "N"

They do need to match exactly. for instance

String: '1,2,3,1a'
Ans: "N"

Using some code I found on this site, I coded this but I'm sure there's a better way. Is there??

--Check for Duplicate combination row values
BEGIN
--Query will split the string into individual pieces.
--Group the pieces to see if any 2 rows are the same
--If no rows are the same then "no_data_found" exception is thrown
SELECT 'T'
INTO vResult

[Code]...