sqlalchemy presto 时间比较

大数据统计时，需要计算开仓订单减掉经纪商时间差，等于n 小时 或 星期几的订单。

presto sql语句如下：

select sum(profit) from t_table where open_time > '1970-01-01 00:00:00.0'
and open_time < '2018-06-02 00:24:18.0' and hour(date_parse(open_time,'%Y-%m-%d %H:%i:%S.%f'))  - 6 = 21;

select sum(profit) from t_table where open_time > '1970-01-01 00:00:00.0'
and open_time < '2018-06-02 00:24:18.0' and dow(date_parse(open_time,'%Y-%m-%d %H:%i:%S.%f'))  - 6 = 2;

sqlalchemy filter条件写法：

filter(extract('hour', cast(t_table.open_time,TIMESTAMP)) - 6 == 21)

--week

filter(extract('dow', cast(cast(t_table.open_time, TIMESTAMP) - text("interval '' hour"),TIMESTAMP))  == 2)