Remove Duplicates From Comma Separated String

Question

Hi,
I have one Column which contains duplicates values with comma separated.
Customer ID
5,5,5,5,6,6,5,5,5,6,7,4,1,2,1,4,7,2
I wrote this:
select REGEXP_REPLACE('5,5,5,5,6,6,5,5,5,6,7,4,1,2,1,4,7,2', '(^|,)([^,]*)(,\2)+','\1\2') from dual;
5,6,5,6,7,4,1,2,1,4,7,2
But it eliminates only continuous elements.
I want out put like:
5,6,7,4,1,2
Please help.
Thanks.
Amit
Edited by: 987565 on Feb 12, 2013 4:02 AM

Answer 1

Thanks Purvesh,
While testing with real data, it is ignoring some values. I didn't understand why it happening.
with data as
select '5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5668,5716,5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5714,5668,5716' col from dual
select ltrim(max(sys_connect_by_path(col, ',')) keep (dense_rank last order by rn - 1), ',') col
from (
select col, row_number() over (order by 1) rn
from (
select distinct regexp_substr(col, '[^,]+', 1, level) col
from data
connect by level <= length(col) - length(replace(col, ','))
start with rn = 1
connect by prior rn = rn - 1;
Result I got is:
5714,5714,5716
My Real Query is like that:
declare
cursor c1 is
select o.id id
from order o;
v_char varchar2(200) := '';
begin
for a1 in c1 loop
with data as
select o.cust_id as col into v_char
from order o
where o.id = a1.id
select ltrim(max(sys_connect_by_path(col, ',')) keep (dense_rank last order by rn - 1), ',') col
from (
select col, row_number() over (order by 1) rn
from (
select distinct regexp_substr(col, '[^,]+', 1, level) col
from data
connect by level <= length(col) - length(replace(col, ','))
start with rn = 1
connect by prior rn = rn - 1;
SYS.dbms_output.put_line(v_char);
end loop;
end;
Later, i will update same cust_id with v_char.