Using sql to delete duplicate records

Hi everyone
Before I forget - we are on V5r4

This is driving me nuts (I know - not that far to drive)
I used the following sql to delete duplicate records in a file
delete from file01 A where rrn(A) in
(select RRN(B) from file01 B, file01 C where
b.IITEM = c.IITEM and RRN(B) > RRN(C))


and received a display the nnn records had been deleted
Don't ask me why - but I ran the same statement again - expecting zero records deleted
But it gave me a smaller number than before
Which surprised me
So I ran it again
And received an even smaller number

I ran this statement multiple time, receiving a smaller number each time

I then ran a RGZPFM to remove all deleted records and ran the sql statement again
Only to be informed that a certain number had been deleted
I ran it again and received notification tha a lesser number had been deleted


Obviously I am doing something wrong - but I cannot see what it is
Does anyone else see what I am doing wrong?

Alan Shore
E-mail : ASHORE@xxxxxxxx
Phone [O] : (631) 200-5019
Phone [C] : (631) 880-8640
'If you're going through hell, keep going.'
Winston Churchill