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Subject: select values from interval
From: Josep =?ISO-8859-1?Q?Sanmart=ED?= <josep.sanmarti@openwired.net>
To: pgsql-sql@postgresql.org
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Date: Mon, 04 Jul 2005 14:00:57 +0200
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Hi,

I've this table: am_conn(mac, user_ip, start_time, end_time). Each time
a user connects with a remote server a new row is added, when the user
is disconnected the end_time field is set.

Now, I want to know if there is a way (sql statement) to know how many
connections are up during an interval time, for example 60 segs, and to
repeat this interval from a beginning date to end date. I think it
should be something like:
	SELECT COUNT(*)
	FROM am_conn
	WHERE start_time between '2004-01-01 10:28:00.000'
		AND end time '2005-01-01 10:28:00.000'
	GROUP BY .....something.....

I made some tests but I can't obtain the correct statement. Maybe,
probably, it should be done without group by.

Thanks.