SQL view for SOP sales by customer by month

Someone asked me for code to get monthly SOP sales and I could have sworn I already had that. But I searched and didn’t come up with anything, so here is a new view to show SOP sales (the total of SOP invoices less returns) by month. As usual, I am making a few assumptions (listed in the view comments), and am hard coding one year at a time (2013 in this example). You can easily change the year as needed on line 59.

create view view_Sales_by_Customer_by_Month
as

-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
-- view_Sales_by_Customer_by_Month
-- Created June 7, 2013
--    by Victoria Yudin - Flexible Solutions, Inc.
-- For updates see http://victoriayudin.com/gp-reports/
-- Returns total sales (invoices - returns) for each customer
--    by month (for the specified year)
-- Amount used is the invoice total (including freight,
--    taxes, discounts, etc.)
-- Only posted invoices and returns are included
-- Shows functional currency
-- Voided transactions are excluded
-- Document Date is used (not GL Posting Date)
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

select
d.CUSTNMBR Customer_ID,
d.CUSTNAME Customer_Name,
sum(case when month(d.DOCDATE) = 1
  then d.SALES else 0 end) Jan_Sales,
sum(case when month(d.DOCDATE) = 2
  then d.SALES else 0 end) Feb_Sales,
sum(case when month(d.DOCDATE) = 3
  then d.SALES else 0 end) Mar_Sales,
sum(case when month(d.DOCDATE) = 4
  then d.SALES else 0 end) Apr_Sales,
sum(case when month(d.DOCDATE) = 5
  then d.SALES else 0 end) May_Sales,
sum(case when month(d.DOCDATE) = 6
  then d.SALES else 0 end) Jun_Sales,
sum(case when month(d.DOCDATE) = 7
  then d.SALES else 0 end) Jul_Sales,
sum(case when month(d.DOCDATE) = 8
  then d.SALES else 0 end) Aug_Sales,
sum(case when month(d.DOCDATE) = 9
  then d.SALES else 0 end) Sep_Sales,
sum(case when month(d.DOCDATE) = 10
  then d.SALES else 0 end) Oct_Sales,
sum(case when month(d.DOCDATE) = 11
  then d.SALES else 0 end) Nov_Sales,
sum(case when month(d.DOCDATE) = 12
  then d.SALES else 0 end) Dec_Sales,
sum(d.SALES) Yearly_Total

from
(select s.DOCDATE, s.CUSTNMBR, c.CUSTNAME,
 case s.SOPTYPE
   when 3 then s.DOCAMNT
   when 4 then s.DOCAMNT*-1
   end SALES
 from SOP30200 s
 left outer join RM00101 c
   on s.CUSTNMBR = c.CUSTNMBR
 where s.VOIDSTTS = 0
   and s.SOPTYPE in (3,4)
   and year(s.DOCDATE) = 2013 --change year as needed
 ) d

group by d.CUSTNMBR, d.CUSTNAME

-- add permissions for DYNGRP
go
grant select on view_Sales_by_Customer_by_Month to DYNGRP

Disclaimer: I tested this on limited data, if you find an issue or have a suggestion for improvement, please let me know and I will post the update here for everyone.