On Oct 13, 2005, at 21:50 , [EMAIL PROTECTED] wrote:
Dear all,
I have a table created with this specifications:
CREATE TABLE cdr (
calldate timestamp with time zone NOT NULL default now(),
clid varchar(80) NOT NULL default '',
src varchar(80) NOT NULL default '',
dst varchar(80) NOT NULL default '',
dcontext varchar(80) NOT NULL default '',
channel varchar(80) NOT NULL default '',
dstchannel varchar(80) NOT NULL default '',
lastapp varchar(80) NOT NULL default '',
lastdata varchar(80) NOT NULL default '',
duration bigint NOT NULL default '0',
billsec bigint NOT NULL default '0',
disposition varchar(45) NOT NULL default '',
amaflags bigint NOT NULL default '0',
accountcode varchar(20) NOT NULL default '',
uniqueid varchar(32) NOT NULL default '',
userfield varchar(255) NOT NULL default ''
);
I want to extract the number of calls placed in 1 hour and the average
call duration
I'm working with this query:
SELECT date_trunc('hour',calldate), duration FROM cdr WHERE src=601
ORDER BY calldate;
i tried several other queries but i'm not able to count the number of
calls in an hour (better in a time interval) and calculate the average
duration.
For a first step, I'd build a view of
create view cdr_by_hour_view as
select date_trunc('hour,calldate) as callhour, duration
from cdr;
Then I'd select from this view using aggregates:
select callhour, avg(duration) as avg_duration
from cdr
where src = 601
group by callhour;
You could write it
This should help you with the simple case of just hourly averages.
For averages on any given interval I think it's a bit more involved
(as general cases generally are).
Hope this helps!
Michael Glaesemann
grzm myrealbox com
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