duplicates

I have a system bug which means that I have occasional dupicate entries in
my 'subscribers' table. I'm trying to find a query which performs something
like a 'where user_name is not unique' query.

At the moment we use this cludge:

select count(*), user_name from subscribersgroup by user_name order by count;

(I'm surprised I can't add 'where count > 1' but it seems conditionals on 
aggregate fields are not allowed).

This gives me a very long list with the 'not unique' entries at the bottom, eg

count | user_name
------+------------------
1     | bill.hicks [ ..cut 9 zillion results.. ]
1     | margaret.thatcher
4     | linus.torvalds
9     | bill.gates

I then have to do 

select oid from subscribers where user_name = 'linus.torvalds';

and delete all but one of the records. Is there a better way to do this?
And yes, we're working on a system fix to avoid the problem in the 1st place!

TIA, al.

-- 
# Allan Kelly                                http://www.plotsearch.co.uk# (+44) (0)131 524 8500#
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