This shows an odd quirk of the date query

date_query_in_mongomapper.rb

require 'rubygems'
require 'mongo_mapper'

MongoMapper.connection = Mongo::Connection.new('127.0.0.1', 27017, :logger => Logger.new(STDOUT))
# MongoMapper.connection = Mongo::Connection.new('127.0.0.1', 27017)
MongoMapper.database = 'testing'


class Person
  include MongoMapper::Document
  
  attr_accessible(:name, :dob)

  # Attributes ::::::::::::::::::::::::::::::::::::::::::::::::::::::
  key :name, String
  key :dob, Time

  def age
    now = Time.now.utc.to_date
    now.year - dob.year - ((now.month > dob.month || (now.month == dob.month && now.day >= dob.day)) ? 0 : 1)
  end
end

Person.destroy_all()

p60 = Person.create( :name => "Foghorn", :dob => Time.parse((Date.today - 60.years).to_s))
p50p = Person.create( :name => "Bugs", :dob => Time.parse(Date.new(1960,1,1).to_s))
p50 = Person.create( :name => "Bugs2", :dob => Time.parse((Date.today - 50.years).to_s))
p40 = Person.create( :name => "Sylvester", :dob => Time.parse((Date.today - 40.years).to_s))
p10 = Person.create( :name => "Elmer", :dob => Time.parse((Date.today - 10.years).to_s))
p2 = Person.create( :name => "Baby A", :dob => Time.parse((Date.today - 2.years).to_s))

t = Time.now - 3.years
# Look for those older than 3 years
older = Person.where(:dob.lte => t).all
# Look for those under 3 years
younger = Person.where(:dob.gt => t).all

puts "-"*25
ppl = Person.all
ppl.each do |p|
  puts "#{p.name}, #{p.age} yrs"
end

puts "*"*25
puts "Older than 3: " 
unless older.nil? || older.empty?
  older.each do |p|
    puts "\t#{p.name}, #{p.age} yrs"
  end
else
  puts "\tNone"
end

puts "Younger than 3: " 
unless younger.nil? || younger.empty?
  younger.each do |p|
    puts "\t#{p.name}, #{p.age} yrs"
  end
else
  puts "\tNone"
end
puts "-"*25

results.txt

-------------------------
Foghorn, 60 yrs
Bugs, 50 yrs
Bugs2, 50 yrs
Sylvester, 40 yrs
Elmer, 10 yrs
Baby A, 2 yrs
*************************
Older than 3: 
	Sylvester, 40 yrs
	Elmer, 10 yrs
Younger than 3: 
	Foghorn, 60 yrs
	Bugs, 50 yrs
	Bugs2, 50 yrs
	Baby A, 2 yrs
-------------------------