select_values

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 55
        def select_values(arel, name = nil)
          arel, binds = binds_from_relation arel, []
          sql = to_sql(arel, binds)
          execute_and_clear(sql, name, binds) do |result|
            if result.nfields > 0
              result.column_values(0)
            else
              []
            end
          end
        end