其中,`date_trunc`函数是一个非常实用且强大的工具,它允许用户根据指定的精度截断时间值,从而获取特定的时间点或时间段。 以`date_trunc`为例,该函数的第一个参数用于指定截断的精度,如年、月、日等。通过这种方式,我们可以轻松地提取出当前年份的第一天(`select date_trunc('year', now()) as 当年第1天`)...
PostgreSQL将日期转为年、月、日的函数date_trunc: 当前年: select date_trunc('year',now()) 当前月: select date_trunc('month',now()) 当前日: select date_trunc('day',now()) 当前时: select date_trunc('hour',now()) 当前分: select date_trunc('minute',now()) 当前秒: select date_trunc...
SELECT TO_CHAR(date1, 'MMDDYYYY:HH24:MI:SS') date1, TO_CHAR(date2, 'MMDDYYYY:HH24:MI:SS') date2, trunc(86400 * (date2 - date1)) - 60 * (trunc((86400 * (date2 - date1)) / 60)) seconds, trunc((86400 * (date2 - date1)) / 60) - 60 * (trunc(((86400 * (date2...
PostgreSQL将日期转为年、月、日的函数date_trunc: 当前年: select date_trunc('year',now()) 当前月: select date_trunc('month',now()) 当前日: select date_trunc('day',now()) 当前时: select date_trunc('hour',now()) 当前分: select date_trunc('minute',now()) 当前秒: select date_trunc...
首先,使用CURRENT_DATE函数获取当前日期。示例:SELECT CURRENT_DATE; 使用DATE_TRUNC函数将当前日期截断为月份,并减去一个月。示例:SELECT DATE_TRUNC('month', CURRENT_DATE) - INTERVAL '1 month'; 使用DATE_PART函数获取上个月的年份和月份。示例:SELECT DATE_PART('year', DATE_TRUNC('month', CURRENT_DAT...
当前年: select date_trunc('year',now()) 当前月: select date_trunc('month',now()) 当前日: select date_trunc('day',now()) 当前时: select date_trunc('hour',now()) 当前分: select date_trunc('minute',now()) 当前秒: select date_trunc('second',now())...
date_trunc(field, source [, time_zone ])函数用于将 timestamp、timestamp with time zone、date、time 或者 interval 数据截断到指定的精度。 SELECTdate_trunc('year',timestamp'2020-03-03 20:38:40'),date_trunc('day',timestamptz'2020-03-03 20:38:40+00','Asia/Shanghai'),date_trunc('hour...
SELECT date_trunc($2, $1 + interval '12 hour') INTO r; ELSIF $2 = 'week' THEN SELECT date_trunc($2, $1 + interval '84 hour') INTO r; ELSIF $2 = 'month' THEN SELECT date_trunc($2, $1 + interval '15 day') INTO r; ELSIF $2 = 'year' THEN SELECT date_trunc($2, $...
⽇期加减： SELECT now() + INTERVAL '1 year 1 month 1 day 1 hour 1 min 1 sec'⽇期加减：SELECT now() :: TIMESTAMP - (列) :: INTERVAL ⽇期截取：SELECT date_trunc ('day', now())数字截取：SELECT trunc(123.456, 2)四舍五⼊：SELECT ROUND(125.56, 1)进位取整：SELECT CEIL(...
PostgreSQLdate_trunc（）和timestamp timestamp 01.SELECT now()::timestamp + '1 year';02.SELECT now()::timestamp + '1 month';03.SELECT now()::timestamp + '1 day';04.SELECT now()::timestamp + '1 hour';05.SELECT now()::timestamp + '1 min';06.SELECT now()::timestamp + '1...