select substr(to_char(t.callintime, ‘yyyy-mm-dd hh24:mi:ss‘),0,15), count(1) from t_ivr_call_log t where t.callintime > trunc(sysdate - 8) and t.callintime < trunc(sysdate) group by substr(to_char(t.callintime, ‘yyyy-mm-dd hh24:mi:ss‘),0,15) order by substr(to_char(t.callintime, ‘yyyy-mm-dd hh24:mi:ss‘),0,15) ;