generate_series 文档说,对于generate_series(start, stop, step interval) ,参数可以是int或bigint用于generate_series(start, stop)和generate_series(start, stop, step)个案, timestamp或timestamp with time zone 。 generate_series与datetypes一起作为input并返回timestamp with timezone的原因是什么? pg=# select generate_series('2014-01-01'::date,'2014-01-02'::date,'1 day'); generate_series ———————— 2014-01-01 00:00:00+01 2014-01-02 00:00:00+01 (2 rows)