stat-graphs-ex1.rb

range = "created_at #{(12.months.ago.to_date..Date.today).to_s(:db)}"
# .to_s(:db) is a helper to transform a date-range into SQL condition clause
#  ex. above: => "created_at BETWEEN '2006-01-05' AND '2007-01-05'" 
 
@users = User.count(:all, :conditions => range, :group => "DATE_FORMAT(created_at, '%Y-%m')", :order =>"created_at ASC")
# - count all users, whose created_at timestamp falls within the range specified above
# - group users by 'Year-Month', and count the number of occurences within each group
# ex. result:
#   count | date
#   ---------------
#     2   | 2005-10
#    24   | 2005-11
#    32   | 2005-12