Date function

I have a table with data on data basis. I want to report all the data with respect to Date for the last 18 months & the most recent month being the previous month.
Can anyone help me on how to create a formula for this .
Thanks in advance
askrhHi!

i dont know exact function for ur problem.

but i hope the following link is useful to clear ur problem.

see this :
http://www.dev-archive.com/forum/showthread.php?p=1198030#post1198030

regards