question with times and intervals

Hi,

I have a table like this:

test=# select * from status_log ;id | status |        t_start         |         t_end
----+--------+------------------------+------------------------ 1 |      1 | 2006-01-20 23:00:00+01 | 2006-01-21
06:00:00+011 |      1 | 2006-01-21 06:00:00+01 | 2006-01-21 22:00:00+01 1 |      2 | 2006-01-21 22:00:00+01 |
2006-01-2205:00:00+01 1 |      1 | 2006-01-22 05:00:00+01 | 2006-01-22 15:00:00+01 1 |      2 | 2006-01-22 15:00:00+01
|2006-01-23 02:00:00+01
 
(5 rows)

Now i need for a particular intervall (one day or two days, entires
days) the accumulated time for id=X and status=Y. 

Exampel:

id=1, status=1, date=2006-01-21:

from 00:00:00 - 06:00:00 and    06:00:00 - 22:00:00

===> 6 hours + 16 hours = 22 hours

id=1, status=2, date=2006-01-21:from 22:00:00 - 23:59:59

===> 2 hours


I need also this for a week or month. How can i calculate this?


Thanks very much for help.
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Andreas Kretschmer    (Kontakt: siehe Header)
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