Include missing months in Group By query

Question

I think I have a tough one here... :(

I am trying to get an order count by month, even when zero. Here\'s the problem query:

SELECT datename(month,          


        

Answer 1

Since your query Just Can't guess the months you want, you will need to have the Months that you want stored in somewhere, Join them with your table, and then group. Something like:

;With Months (Month) 
AS
(

    select 'January' as Month
    UNION
    select 'February' as Month
    UNION
    select 'March' as Month
    UNION
    select 'April' as Month
    UNION
    select 'May' as Month
    UNION
    select 'June' as Month
    UNION
    select 'July' as Month
    UNION
    select 'August' as Month
    UNION
    select 'September' as Month
    UNION
    select 'October' as Month
    UNION
    select 'November' as Month
    UNION
    select 'December' as Month

)
--Also you could have them in a "Months" Table

Then Just JOIN this table with your table:

   Select 
    SELECT datename(month, OrderDate) as Month, COUNT(OrderNumber) 
    FROM Months T1
    LEFT JOIN OrderTable T2 on datename(month, T2.OrderDate) = T2.Month
    WHERE (T2.OrderDate >= '2012-01-01' and T2.OrderDate <= '2012-06-30') 
OR T2.OrderDate IS NULL --So will show you the months with no rows
    GROUP BY year(T2.OrderDate), month(T2.OrderDate), datename(month, T2.OrderDate)

Hope it works!