Log switches per hour and archive log space

Find the log switches with following query: SELECT TRUNC (first_time) "Date", TO_CHAR (first_time, 'Dy') "Day",<br>COUNT (1) "Total",<br>SUM (DECODE (TO_CHAR (first_time, 'hh24'), '00', 1, 0)) "h0",<br>SUM (DECODE (TO_CHAR (first_time, 'hh24'), '01', 1, 0)) "h1",<br>SUM (DECODE (TO_CHAR (first_time, 'hh24'), '02', 1, 0))…
