Question

I have the following set of data:

ID  |  CREATED     |  USER
--------------------------
1   |  2012-01-14  |   XYZ
2   |  2012-03-14  |   XYZ
3   |  2012-03-15  |   XYZ
4   |  2012-03-24  |   ABC
5   |  2012-04-10  |   XYZ
6   |  2012-04-11  |   ABC

And I need a report that shows the COUNT for a given user but also with a 0 for months where there are no records.

MTH  |  COUNT
-------------
JAN  |   1
FEB  |   0
MAR  |   2
APR  |   1

I managed to get it to work but without the 0 for months with no records. So far, I have this syntax which is throwing an error..

SELECT Month(CREATED), COUNT(SELECT * FROM SEARCHES WHERE USER = 'XYZ')
FROM SEARCHES
GROUP BY Month(CREATED)

Answer 1

Here is general query for grouping by date range. @startDate and @endDate define the range; you might set min(created) and max(created) for user, or some fixed range.

CTE monthlyRange generates table of months – first of current month, first of next month. Searches is later left-joined to monthlyRanges by created. Note that user is filtered in join as this is left join and filtering in where clause would effectively turn it into inner join.

declare @startDate datetime
declare @endDate datetime
set @startDate = '2012-01-01'
set @endDate = '2013-01-01'

; with monthlyRange (startMonth, startNextMonth) as (
  select dateadd (m, datediff (m, 0, @startDate), 0),
         dateadd (m, datediff (m, 0, @startDate) + 1, 0)
  union all
  select dateadd (m, 1, startMonth),
         dateadd (m, 1, startNextMonth)
    from monthlyRange
  where startNextMonth <= dateadd (m, datediff (m, 0, @endDate), 0)
)
SELECT Year(monthlyRange.startMonth) Year, 
       Month(monthlyRange.startMonth) Month, 
       COUNT(searches.Created) Count
  FROM monthlyRange 
  left join SEARCHES
    on monthlyRange.startMonth <= Searches.Created
   and monthlyRange.startNextMonth > Searches.Created
   and [USER] = 'XYZ'
GROUP BY Year(monthlyRange.startMonth), Month(monthlyRange.startMonth)
order by 1, 2

Here is Sql Fiddle for testing