In my column A is a date record (dd/mm/yy), column B is salesman, column C is
product sold and Column D is the quantity value of product sold.

I wish to have a report which in column A is the salesman, B is the month
(January - December in words), C is the product and D is the sum of the
particular month and particular goods had sold.

Without having an extra column to record in the month in words. How can I
capture the value by month with using SUMIF since the format is dd/mm/yy?