SQLAlchemy的过滤器时区

Question

更新

@datetime_as_timestamp.expression 
def datetime_as_timestamp(cls): 
    return db.func.timestamp(cls.date, cls.time) 

到

@datetime_as_timestamp.expression 
def datetime_as_timestamp(cls): 
    return cls.date + cls.time 

原始

我有日期和时间在我的模型。在另一个表中有他们的时区，但为了简单起见，我会手动完成。我想按日期+时间+时区过滤。

class Foo(db.Model): 
    id = db.Column(db.Integer, primary_key=True) 
    date = db.Column(db.Date) 
    time = db.Column(db.Time) 

    @hybrid_property 
    def datetime_as_timestamp(self): 
     return time.mktime(
      datetime.datetime.combine(self.date, self.time).timetuple() 
     ) 

    @datetime_as_timestamp.expression 
    def datetime_as_timestamp(cls): 
     return db.func.timestamp(cls.date, cls.time) 

但是，当我执行过滤查询

In [1]: Foo.query.filter(func.timezone('Australia/Brisbane', Foo.datetime_as_timestamp) <= func.timezone('UTC', func.current_timestamp())).one() 

我得到一个错误

psycopg2.ProgrammingError) syntax error at or near "foo" 
LINE 3: WHERE timezone('Australia/Brisbane', timestamp(foo.da... 
               ^
[SQL: 'SELECT foo.id AS checkin_flight_id, foo.date AS checkin_flight_date, foo.time AS checkin_flight_time \nFROM foo \nWHERE timezone(%(timezone_1)s, timestamp(foo.date, foo.time)) <= timezone(%(timezone_2)s, CURRENT_TIMESTAMP)'] [parameters: {'timezone_2': 'UTC', 'timezone_1': 'Australia/Brisbane'}] 

我缺少什么，哪里是我的错？是否有可能以另一种方式解决我的问题？

Answer 1

我发现这个Q&A非常有帮助。我改变

@datetime_as_timestamp.expression 
def datetime_as_timestamp(cls): 
    return db.func.timestamp(cls.date, cls.time) 

到

@datetime_as_timestamp.expression 
def datetime_as_timestamp(cls): 
    return cls.date + cls.time 

和一切工作正常