select h.event, h.client_id, h.BLOCKING_SESSION, h.BLOCKING_SESSION_SERIAL# , H.CURRENT_BLOCK#, H.CURRENT_OBJ#, 
H.CURRENT_ROW#,o.owner || '.' || o.object_name as obj_name, COUNT(*) as cnt , COUNT(DISTINCT H.SESSION_ID) as sid_cnt,
'select * from '||o.owner || '.' || o.object_name||' where SYS.dbms_rowid.rowid_block_number(rowid) = '||H.CURRENT_BLOCK#||' and SYS.dbms_rowid.rowid_row_number(rowid) = ' || H.CURRENT_ROW# as sql_text
from dba_hist_active_sess_history h 
left join dba_objects o on o.object_id = H.CURRENT_OBJ#
where h.sample_time between :ST_DT and :ED_DT
and sql_id = :SQL_ID
AND h.BLOCKING_SESSION IS NOT NULL
GROUP BY h.event, h.BLOCKING_SESSION, h.BLOCKING_SESSION_SERIAL# , H.CURRENT_BLOCK#, H.CURRENT_OBJ#, H.CURRENT_ROW#,o.owner, o.object_name, h.client_id
order by cnt desc