A. Kretschmer wrote:
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+01
1 | 1 | 2006-01-21 06:00:00+01 | 2006-01-21 22:00:00+01
1 | 2 | 2006-01-21 22:00:00+01 | 2006-01-22 05:00:00+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
OK - all untested...
First step - don't ask for a date, ask between two timestamptz's (which
I'll call t1, t2)
Then, define two functions: earlier(timestamptz, timesatmptz) and
later(...) as SQL functions using SELECT ... CASE
SELECT
later(T1, t_start) AS lower_time
earlier(T2, t_end) AS upper_time
FROM
status_log
WHERE
id = X
AND status = Y
AND ts_end >= T1
AND ts_start <= T2
;
Now (upper_time - lower_time) is the interval you want and summing them
will give you your answer.
Any help?
--
Richard Huxton
Archonet Ltd
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