在PostgreSQL中从没有时区的时间戳中提取EPOCH值

Question

运行此PostgreSQL查询时出现以下错误。谁能告诉我如何更正此查询？

SQL错误：

ERROR:  syntax error at or near "fitacf_data"
LINE 1: ...fitacf_data.num_pts, EXTRACT(EPOCH FROM TIMESTAMP fitacf_dat...
                                                             ^

SELECT fitacf_data.file_date, fitacf_data.num_pts, EXTRACT(EPOCH FROM TIMESTAMP fitacf_data.time), fitacf_data.stcode FROM fitacf_data WHERE fitacf_data.file_date BETWEEN '2017-04-14 00:00:00' AND '2017-04-14 23:59:59' AND fitacf_data.stcode = 'pgr';

Answer 1

如果fitacf_data.time已经是timestamp，请不要使用TIMESTAMP关键字，这是原义的。

...
EXTRACT(EPOCH FROM fitacf_data.time)
...