title: ORA-00920: invalid relational operator
body: <p>This SQL query seems to be hitting ORA 00920.</p>
  
  <pre><code>select username, count(*)
  from host
  where created_dt 
  between to_date('2012-may-23 00:00:00', 'yyyy-mon-dd hh24:mi:ss') 
  and to_date('2012-may-23 23:59:59', 'yyyy-mon-dd hh24:mi:ss')
  GROUP BY CASE
               WHEN REGEXP_LIKE(username, '^\d+$') THEN 'GRP_OTHERS'
                                                   ELSE username
           END;
  </code></pre>