Postgres - 按时间间隔查询时间序列组

Question

我有一个表格BusInfo，它存储了乘客上车的人数以及他/她可以占据多少个座位（取决于他/她拥有的行李数）。 我创建了一个捣鼓IT-

http://sqlfiddle.com/#!15/88226/11

start      end     bus_name seats start_time ride_time 
April, 28 2016 17:00:00 April, 28 2016 18:00:00 CA  2 1461862800  3600 
April, 28 2016 17:30:00 April, 28 2016 18:30:00 CA  1 1461864600  3600 
April, 28 2016 17:45:00 April, 28 2016 18:45:00 CA  2 1461865500  3600 
April, 28 2016 17:00:00 April, 28 2016 19:00:00 CA  1 1461862800  7200 
April, 28 2016 17:00:00 April, 28 2016 17:30:00 CA  2 1461862800  1800 

我想运行一个查询其在10分钟interval.Something这样得到座位占用是预期的输出

datetime | seats occupied at the time 
17:00 5 
17:10 5 
17:20 5 
17:30 4 
17:40 4 
17:50 6 
18:00 4 

我试过，但没有接近 -

select to_char(to_timestamp(floor((extract('epoch' from to_timestamp(start_time))/ 600))*600),'yyyy/MM/dd HH24:MI'), 
       sum(seats) from businfo 

where start_time >= 1461862800 and start_time <= 1461866400 
and (start_time+ride_time) >= (1461862800) 
group by to_char(to_timestamp(floor((extract('epoch' from  
to_timestamp(start_time))/ 600))*600),'yyyy/MM/dd HH24:MI') 
order by to_char(to_timestamp(floor((extract('epoch' from 
     to_timestamp(start_time))/ 600))*600),'yyyy/MM/dd HH24:MI') ASC 

有什么想法？

Answer 1

一种方法是使用generate_series()：

select gs.ts, sum(seats) 
from generate_series('2016-04-28 17:00:00'::timestamp, '2016-04-28 18:00:00', interval '10 minute') gs(ts) join 
    businfo bi 
    on gs.ts between bi.start and bi.end 
group by gs.ts 
order by gs.ts;