[tom_b]

A little flaky perhaps, but if you're gonna love sql :-)

select distinct cnt, count(cnt) over (partition by cnt) from (

select 'a' usr,1 cnt from dual union select 'b' usr,1 cnt from dual union select 'c' usr,2 cnt from dual union select 'd' usr,3 cnt from dual union select 'e' usr,3 cnt from dual )