merge_conditions

# File activerecord/lib/active_record/base.rb, line 1488
        def merge_conditions(*conditions)
          segments = []

          conditions.each do |condition|
            unless condition.blank?
              sql = sanitize_sql(condition)
              segments << sql unless sql.blank?
            end
          end

          "(#{segments.join(') AND (')})" unless segments.empty?
        end