sqltypes.py 文件源码

def _expression_adaptations(self):
        return {
            operators.add: {
                Integer: self.__class__,
                Interval: DateTime,
                Time: DateTime,
            },
            operators.sub: {
                # date - integer = date
                Integer: self.__class__,

                # date - date = integer.
                Date: Integer,

                Interval: DateTime,

                # date - datetime = interval,
                # this one is not in the PG docs
                # but works
                DateTime: Interval,
            },
        }