Ruby on Rails, find by two conditions -

i trying find values of given model combination of 2 fields.

i have following model:

  create_table "users", :force => true |t|     t.string   "name"     t.string   "url"     t.integer  "clicks_given"     t.integer  "clicks_received"     t.datetime "created_at"     t.datetime "updated_at"   end 

and have defined method model:

  def credits     credits = self.clicks_given - self.clicks_received   end 

i trying find users above given credits:

  @users = user.find(:all, :conditions => { "credits >= ?", -5 }) 

and:

  @users = user.find(:all, :conditions => { "clicks_given - clicks_received >= ?", -5 }) 

fail. should correct statement to find right users?

pass condition array instead of hash:

@users = user.find(:all, :conditions => [ "clicks_given - clicks_received >= ?", -5 ]) 

the first version not work since "credits" not database column.

edit:

or in rails 3 syntax, order:

@users = user.where("clicks_given - clicks_received >= ?", 5).order("clicks_given - clicks_received")