1.转化为秒 SELECT date_part('epoch', TIMESTAMP '2021-08-17 21:00:00' - TIMESTAMP '2021-08-17 20:00:00') 秒; --结果：3600 2.转化为分 SELECT date_part('epoch', TIMESTAMP '2021-08-17 21:00:00' - TIMESTAMP '2021-08-17 20:00:00')/60 分钟; --结果：60 3.转化为时 SELECT date_part('epoch', TIMESTAMP '2021-08-17 21:00:00' - TIMESTAMP '2021-08-17 20:00:00')/60/60 小时; --结果：1 4.转化为天 SELECT date_part('epoch', TIMESTAMP '2022-08-17 20:00:00' - TIMESTAMP '2021-08-17 20:00:00')/60/60/24 天; --结果：365， century decade year month day hour minute second microseconds milliseconds dow doy epoch isodow isoyear timezone timezone_hour timezone_minute