Eliminate rows in a windows of x seconds

Question

Hi,
Please consider the following case:
I have a table with millions of rows.
I need to eliminate from the statement results each set of rows (two or more) , which exists in a window of 60 second.
For example:
create table test
(id number,
b date);
insert into test values(1,to_date('01/01/2012 16:00:10','dd/mm/yyyy hh24:mi:ss'));
insert into test values(2,to_date('01/01/2012 16:00:20','dd/mm/yyyy hh24:mi:ss'));
insert into test values(3,to_date('01/01/2012 16:03:10','dd/mm/yyyy hh24:mi:ss'));
insert into test values(4,to_date('01/01/2012 16:45:50','dd/mm/yyyy hh24:mi:ss'));
insert into test values(5,to_date('01/01/2012 16:46:20','dd/mm/yyyy hh24:mi:ss'));
insert into test values(6,to_date('01/01/2012 18:59:50','dd/mm/yyyy hh24:mi:ss'));
commit;
select id , to_char(b, '/dd/mm/yyyy hh24:mi:ss') from test;
SQL> select id , to_char(b, '/dd/mm/yyyy hh24:mi:ss') from test;
        ID TO_CHAR(B,'/DD/MM/YY
         1 /01/01/2012 16:00:10
         2 /01/01/2012 16:00:20
         3 /01/01/2012 16:03:10
         4 /01/01/2012 16:45:50
         5 /01/01/2012 16:46:20
         6 /01/01/2012 18:59:50 -- Based on the logic above only id : 3 and 6 should be return from the statments.
I succeeded to eliminate the rows which are in the very same minute (id 1 +2 ) but not in a windows of 60 seconds
such as id 4+5 .
Please advice

Answer 1

Like this?
SQL> ed
Wrote file afiedt.buf
  1  select id, b
  2  from (
  3        select id, b
  4              ,case when abs(b-lag(b) over (order by b)) < (1/(24*60))
  5                      or abs(b-lead(b) over (order by b)) < (1/(24*60))
  6               then 0
  7               else 1
  8               end as chk
  9        from test
10       )
11* where chk = 1
SQL> /
        ID B
         3 01-JAN-2012 16:03:10
         6 01-JAN-2012 18:59:50Edited by: BluShadow on 07-Jun-2012 14:08
ps. you may want to have the condition as "<=" rather than "<" depending on what you mean by "in" the window of 60 seconds.