I have imported some rows from a spreasheet. each column is named by date
[15-1-2010], [15-2-2011] and so on for 12 months
how do i create a query that willl tell me which codes are new codes in the following month
in this example codes in 15-2-2010 that do not appear in 15-1-2010. I need to do that for all the months.