SQL How to show '0' value for a month, if no data exists in the table for that month

Answer 1

if you don't want to do all that you could also modify this: SUM(BELOP) with this: Sum (case when BELOP is not null then 1 else 0 end)

Answer 2

You can query a table with the values 1-12 and left outer join your result.

Here is a sample using a table variable instead of your query and a CTE to build a table with numbers.

declare @T table
(
  Month int
)

insert into @T values(1)
insert into @T values(1)
insert into @T values(1)
insert into @T values(3)
insert into @T values(3)

;with Months(Month) as
(
  select 1
  union all
  select Month + 1
  from Months
  where Month < 12
)
select M.Month,
       count(T.Month) Count,
       isnull(sum(T.Month), 0) Sum
from Months as M
  left outer join @T as T
    on M.Month = T.Month
group by M.Month

Result:

Month       Count       Sum
----------- ----------- -----------
1           3           3
2           0           0
3           2           6
4           0           0
5           0           0
6           0           0
7           0           0
8           0           0
9           0           0
10          0           0
11          0           0
12          0           0

Answer 3

You can also add in the year if you have a creation date for the interactions you are counting which may be helpful if your interactions span the course of many years.

with Months(Month) as
(
  select 1
  union all
  select Month + 1
  from Months
  where Month < 12
)
select M.Month, year(CreatedOn) as Year,
       count(amount) Count,
       isnull(sum(amount), 0) Sum
from Months as M
  left outer join Charge as C
    on M.Month = (month(CreatedOn))
group by M.Month, year(CreatedOn) order by year(CreatedOn)