1405     def visit_constant(self, constant):

  1405     def visit_constant(self, constant):

  1406         """generate SQL name for a constant"""

  1406         """generate SQL name for a constant"""

  1407         if constant.type is None:

  1407         if constant.type is None:

  1408             return 'NULL'

  1408             return 'NULL'

  1409         value = constant.value

  1409         value = constant.value

  1410         if constant.type == 'Int' and  isinstance(constant.parent, SortTerm):

  1412         if constant.type == 'Int' and  isinstance(constant.parent, SortTerm):

  1411             return value

  1413             return value

  1412         if constant.type in ('Date', 'Datetime'):

  1414         if constant.type in ('Date', 'Datetime'):

  1413             rel = constant.relation()

  1415             rel = constant.relation()

  1414             if rel is not None:

  1416             if rel is not None: