attribute_condition

# File activerecord/lib/active_record/base.rb, line 1855
        def attribute_condition(argument)
          case argument
            when nil   then "IS ?"
            when Array, ActiveRecord::Associations::AssociationCollection, ActiveRecord::NamedScope::Scope then "IN (?)"
            when Range then "BETWEEN ? AND ?"
            else            "= ?"
          end
        end