> On Mar 17, 2015, at 8:09 AM, Paul Jungwirth <pj@xxxxxxxxxxxxxxxxxxxxxxxx> wrote: > >>> test=> select h, count(*) from start_end, generate_series(0, 23) as s(h) where h between extract(hour from start_time) and extract(hour from end_time) group by h order by h; >>> >>> h | count >>> ----+------- >>> 8 | 2 >>> 9 | 3 >>> 10 | 2 >>> 11 | 2 > > Note if you always want all 24 rows with a count of 0 when appropriate (which seems common in reports with tables or plots), you can just tweak the above query to use a left join: FROM generate_series(0, 23) AS s(h) LEFT OUTER JOIN start_end ON h BETWEEN ... > > Paul Right, thanks. That makes sense. So next question: how do I get the "active" time per hour from this? To use the same example that came up with this result set: Given this: test=> select * from start_end ; id | start_time | end_time ----+------------------------+------------------------ 1 | 2015-03-16 08:15:00-07 | 2015-03-16 09:35:00-07 2 | 2015-03-16 09:15:00-07 | 2015-03-16 11:05:00-07 3 | 2015-03-16 08:00:00-07 | 2015-03-16 11:45:00-07 The specified query returns this: h | count ----+------- 8 | 2 9 | 3 10 | 2 11 | 2 Which is an excellent start, but I also need one more column, which is the total "active" time per hour. So given the intermediate result of this: id | start_time | end_time | h ----+------------------------+------------------------+---- 1 | 2015-03-16 08:15:00-07 | 2015-03-16 09:35:00-07 | 8 3 | 2015-03-16 08:00:00-07 | 2015-03-16 11:45:00-07 | 8 1 | 2015-03-16 08:15:00-07 | 2015-03-16 09:35:00-07 | 9 2 | 2015-03-16 09:15:00-07 | 2015-03-16 11:05:00-07 | 9 3 | 2015-03-16 08:00:00-07 | 2015-03-16 11:45:00-07 | 9 2 | 2015-03-16 09:15:00-07 | 2015-03-16 11:05:00-07 | 10 3 | 2015-03-16 08:00:00-07 | 2015-03-16 11:45:00-07 | 10 2 | 2015-03-16 09:15:00-07 | 2015-03-16 11:05:00-07 | 11 3 | 2015-03-16 08:00:00-07 | 2015-03-16 11:45:00-07 | 11 I'd want a final result of this: h | count | sum ----+--------------- 8 | 2 | 1.75 (or 1:45:00 or whatever) 9 | 3 | 2.33 (2:20:00) 10 | 2 | 2.00 (2:00:00) 11 | 2 | 0.83 (0:50:00) Where the 1:45 in the 8 hour is based on 45 minutes from row id 1 [8:15-9:00) plus the full hour [08:00-9:00) from row id 3, the hour 9 value is based on the amount of rows 1,2 and 3 that fall within the 9 hour, etc. ----------------------------------------------- Israel Brewster Systems Analyst II Ravn Alaska 5245 Airport Industrial Rd Fairbanks, AK 99709 (907) 450-7293 ----------------------------------------------- > > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
