大數據統計時，需要計算開倉訂單減掉經紀商時間差，等於n 小時 或 星期幾的訂單。

presto sql語句如下：

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條件寫法：

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

--week

filter(extract(‘dow‘, cast(cast(t_table.open_time, TIMESTAMP) - text("interval ‘6‘ hour"),TIMESTAMP
 
))  == 2)

sqlalchemy presto 時間比較