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 subscribers
group 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
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