Comparing sequential values

[JohnnyG23]

Hello, I currently have a table that is full of copier information. What I am trying to do is figure out if there is a ten percent difference in BW copies over a months time. Currently the table looks like this.

CopiersID Month Year BWCount
5 9 2008 7871155
5 10 2008 8100846
5 11 2008 8347935
5 12 2008 8520108
5 1 2009 8774620
5 2 2009 8954160
5 3 2009 9144300
5 4 2009 9297442
5 5 2009 9736422
6 1 2009 7382529
6 5 2009 8190420
7 6 2009 37048
7 7 2009 39436
7 8 2009 41639
9 5 2009 1858
9 6 2009 2290
9 7 2009 3883
etc...


I am trying to find some way to compare, lets say Copier 5 and see if month 5 had ten percent more BW copies than month 4. Can someone tell me a way to do this? I also need it to read previous years to, like when next January comes it will need to compare

Month Year
1 2010
12 2009

and see if the BWCount is a ten percent difference. I am hoping this is something that can be done in a separate table, but if not, that will be OK. If I need to explain in more detail please tell me. I tried getting the table formatted so it would look good but had no luck on everything I tried so imagine everything scooted to the right a little bit. Thanks.

 

[pbaldy]

You can use a technique like this to get the previous value into the current record. From there the math should be easy:

http://www.baldyweb.com/PrevValue.htm

Paul
MS Access MVP 2007/2008