Thanks for the quick reply. I acknowledge that the design is not optimal (I am new to this), so any thoughts you might have to improving it would be great.
My database has the following fields: Year, Peak1, Peak2, Peak3, ... Peak12 representing the maximum for each month of the year. What I would like to do now is a winter peak which would be the maximum of Peak11 and Peak12 of Year-1 and January through March of the current year, and a summer peak that would be the maximum of Peak4 through Peak10.
I believe that your solution would find the summer peak. I thought I could create new fields in the query called Peak11LastYear and Peak12LastYear to resolve my need for a winter peak.
I would appreciate any additional comments on either my design or the calculations. I did come up with the right answer in my test data using a series of nested IIf statements, but it was really tedious.