PostgreSQL 时间类型

官网 datetime 介绍

首先，postgre 并没有 datetime 类型，只有如下这些类型。

Name	Storage Size	Description	Low Value	High Value	Resolution
timestamp [ (*p*) ] [ without time zone ]	8 bytes	both date and time (no time zone)	4713 BC	294276 AD	1 microsecond
timestamp [ (*p*) ] with time zone	8 bytes	both date and time, with time zone	4713 BC	294276 AD	1 microsecond
date	4 bytes	date (no time of day)	4713 BC	5874897 AD	1 day
time [ (*p*) ] [ without time zone ]	8 bytes	time of day (no date)	00:00:00	24:00:00	1 microsecond
time [ (*p*) ] with time zone	12 bytes	time of day (no date), with time zone	00:00:00+1559	24:00:00-1559	1 microsecond
interval [ *fields* ] [ (*p*) ]	16 bytes	time interval	-178000000 years	178000000 years	1 microsecond

在 python 的 SQLAlchemy 框架中，DATETIME 类型对应 PostgreSQL 的 timestamp without time zone