http://www.dba-oracle.com/oracle_tips_sizing_advisor.htm set lines 120; set pages 9999; SELECT to_char(first_time,'YYYY-MON-DD') day, to_char(sum(decode(to_char(first_time,'HH24'),'00',1,0)),'999') "00", to_char(sum(decode(to_char(first_time,'HH24'),'01',1,0)),'999') "01", to_char(sum(decode(to_char(first_time,'HH24'),'02',1,0)),'999') "02", to_char(sum(decode(to_char(first_time,'HH24'),'03',1,0)),'999') "03", to_char(sum(decode(to_char(first_time,'HH24'),'04',1,0)),'999') "04", to_char(sum(decode(to_char(first_time,'HH24'),'05',1,0)),'999') "05", to_char(sum(decode(to_char(first_time,'HH24'),'06',1,0)),'999') "06", to_char(sum(decode(to_char(first_time,'HH24'),'07',1,0)),'999') "07", to_char(sum