sql 分页

select * from (SELECT tt.* ,ROWNUM as rr
  FROM (  SELECT T0mc.displayname, T0mc.classifierid, COUNT (*) 
            FROM md_instance T0mi, md_classifier T0mc, md_namespace T0mn
           WHERE T0mi.enddatetime =
                    TO_DATE ('9999-12-31 23-59-59', 'yyyy-MM-dd hh24-mi-ss')
                 AND T0mi.classifierid = T0mc.classifierid
                 AND T0mi.instanceid = T0mn.owningmodelelementid
        GROUP BY T0mc.displayname, T0mc.classifierid
        ORDER BY T0mc.displayname, T0mc.classifierid)   tt)
WHERE Rr >11 AND Rr < 21