Postgresql group month wise with missing values

Question

first an example of my table:

id_object;time;value;status
1;2014-05-22 09:30:00;1234;1
1;2014-05-22 09:31:00;2341;2
1;2014-05-22 09:32:00;1234;1
...
1;2014-0         


        

Answer 1

you can use generate_series() function like this:

select
    g.month,
    count(m)
from generate_series(1, 12) as g(month)
    left outer join my_table as m on
        m.id_object = 1 and
        m.status = 1 and
        extract(year from m.time) = 2014 and
        extract(month from m.time) = g.month
group by g.month
order by g.month

sql fiddle demo