--列出Oracle日志文件切换的频率图
SELECT trunc(first_time) "日期",
to_char(first_time, 'Dy') "星期",
count(1) "总数",
round(24*60/count(1), 2) "平均每次切换分钟",
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$log_history
--FROM gV$log_history
group by trunc(first_time), to_char(first_time, 'Dy')
Order by 1 desc