Oracle数据库有一个比较常用的SQL，用来计算每个小时的归档日志量，与楼主所表的的类似：

SELECT trunc(first_time) "Date",

to_char(first_time, 'Dy') "Day",

count(1) "Total",

SUM(decode(to_char(first_time, 'hh24'),'00',1,0)) "h0",

SUM(decode(to_char(first_time, 'hh24'),'01',1,0)) "h1",

SUM(decode(to_char(first_time, 'hh24'),'02',1,0)) "h2",

SUM(decode(to_char(first_time, 'hh24'),'03',1,0)) "h3",

SUM(decode(to_char(first_time, 'hh24'),'04',1,0)) "h4",

SUM(decode(to_char(first_time, 'hh24'),'05',1,0)) "h5",

SUM(decode(to_char(first_time, 'hh24'),'06',1,0)) "h6",

SUM(decode(to_char(first_time, 'hh24'),'07',1,0)) "h7",

SUM(decode(to_char(first_time, 'hh24'),'08',1,0)) "h8",

SUM(decode(to_char(first_time, 'hh24'),'09',1,0)) "h9",

SUM(decode(to_char(first_time, 'hh24'),'10',1,0)) "h10",

SUM(decode(to_char(first_time, 'hh24'),'11',1,0)) "h11",

SUM(decode(to_char(first_time, 'hh24'),'12',1,0)) "h12",

SUM(decode(to_char(first_time, 'hh24'),'13',1,0)) "h13",

SUM(decode(to_char(first_time, 'hh24'),'14',1,0)) "h14",

SUM(decode(to_char(first_time, 'hh24'),'15',1,0)) "h15",

SUM(decode(to_char(first_time, 'hh24'),'16',1,0)) "h16",

SUM(decode(to_char(first_time, 'hh24'),'17',1,0)) "h17",

SUM(decode(to_char(first_time, 'hh24'),'18',1,0)) "h18",

SUM(decode(to_char(first_time, 'hh24'),'19',1,0)) "h19",

SUM(decode(to_char(first_time, 'hh24'),'20',1,0)) "h20",

SUM(decode(to_char(first_time, 'hh24'),'21',1,0)) "h21",

SUM(decode(to_char(first_time, 'hh24'),'22',1,0)) "h22",

SUM(decode(to_char(first_time, 'hh24'),'23',1,0)) "h23"

FROM V$log_history

where trunc(first_time)>sysdate-30

group by trunc(first_time), to_char(first_time, 'Dy')

Order by 1;