Question

I have a table in production with 12 columns for each month. I need to create a SP where I pass in a productID, Customer and Month parameter and retrieve the sum of that month.

currently my logic is

if month = 1 then
  select sum(JAN) from table where productID = @id and customer = @cust
if month = 2 then
   select SUM(FEB) from table where productID = @id and customer = @cust

....

The query is a bit more involved but this is the core of it. Is there any way around these “IF” statements?

Edit – This is an SQL Server 2000 database but will be migrated to SQL Server 2005, the PIVOT and UNPIVOT will come in handy when I move to SQL Server 2005.

Answer 1

select sum(case when @month = 1 then Jan
        when @month = 2 then Feb
        when @month = 3 then Mar
        when @month = 4 then Apr
        when @month = 5 then May
        when @month = 6 then Jun
        when @month = 7 then Jul
        when @month = 8 then Aug
        when @month = 9 then Sep
        when @month = 10 then Oct
        when @month = 11 then Nov
        when @month = 12 then [Dec] end) 
        from mytable
        where productID = @id and customer = @cust 

Assuming you declare and inialize the variables, this should work. It’s more complicated of course if you wan to do multiple months, that’s one reason why the design is not the best for querying.