postgreSql——时区问题

时间：2024-04-30 21:08:01
timestamptz、timestamp
SELECT ts AT TIME ZONE 'UTC'

FROM  (

   VALUES

      (timestamptz '2012-03-05 17:00:00+0')

    , (timestamptz '2012-03-05 18:00:00+1')

    , (timestamp   '2012-03-05 18:00:00+1')  -- ① loaded footgun!

    , (timestamp   '2012-03-05 11:00:00'  AT TIME ZONE '+6')

    , (timestamp   '2012-03-05 17:00:00'  AT TIME ZONE 'UTC')

    , (timestamp   '2012-03-05 07:00:00'  AT TIME ZONE 'US/Hawaii')  -- ②

    , (timestamp   '2012-03-05 07:00:00'  AT TIME ZONE 'HST')  -- ②

      ) t(ts);

 SELECT timestamptz '2012-03-05 20:00+03',

	timestamp '2012-03-05 17:00:00' AT TIME ZONE 'UTC',

	timestamp '2012-03-05 17:00:00' AT TIME ZONE 'UTC' AT TIME ZONE 'UTC'

　　

　　

查看现在距1970-01-01 00:00:00 UTC 的秒数

select extract(epoch from now());

select timestamp without time zone 'epoch',timestamp without time zone 'epoch' + 3600*interval '1 sec'

select timestamp without time zone 'epoch',timestamp with time zone 'epoch'

　　

　　

　

把epoch 值转换回时间戳

select timestamp without time zone 'epoch',timestamp with time zone 'epoch' ,timestamp 'epoch',timestamptz 'epoch'

　　

PostgreSQL的时间/日期函数使用

postgreSQL格式化时间的函数详解

mysql转为postgesql

SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(UTC_TIMESTAMP()) + tz.gmt_offset, '%a, %d %b %Y, %H:%i:%s') AS local_time

FROM  "Dict"."TimeZoneDetail" tz JOIN  "Dict"."TimeZoneToCountry" z

ON tz.zone_id=z.zone_id

WHERE tz.time_start <= UNIX_TIMESTAMP(UTC_TIMESTAMP()) AND z.zone_name='America/Los_Angeles'

ORDER BY tz.time_start DESC LIMIT 1;

SELECT (now() AT TIME ZONE 'UTC' )+interval '1'* tz."GMTOffset" AS local_time,now() as now,now() AT TIME ZONE 'UTC' as utcnow,tz."GMTOffset" as offsett

FROM  "Dict"."TimeZoneDetail" tz inner JOIN  "Dict"."TimeZoneToCountry" z

ON tz."ZoneId"=z."ZoneId"

WHERE to_timestamp(tz."TimeStart") <= timestamp 'epoch' AND z."ZoneName"='America/Los_Angeles'

ORDER BY tz."TimeStart" DESC LIMIT 1;

　　

postgreSql——时区问题

postgreSql——时区问题

函数 返回类型 描述

示例

 结果
age(timestamp, timestamp) interval 计算两个时间戳的时间间隔

select age(timestamp '2001-04-10',

timestamp '1957-06-13');

 43 years 9 mons 27 days
age(timestamp) interval 计算current_date与入参时间戳的时间间隔

select age(timestamp

'2016-07-07 12:00:00');

 12:00:00
clock_timestamp() timestamp with time zone 当前时间戳（语句执行时变化） select clock_timestamp(); 2016-07-08 15:14:04.197732-07
current_date date 当前日期 select current_date; 2016-07-08
current_time time with time zone 当前时间 select current_time; 15:15:56.394651-07
current_timestamp timestamp with time zone 当前时间戳 select current_timestamp; 2016-07-08 15:16:50.485864-07
date_part(text, timestamp) double precision 获取时间戳中的某个子域，其中text可以为year,month,day,hour,minute,second等

select

date_part('year',timestamp'2016-07-08 12:05:06'),

date_part('month',timestamp'2016-07-08 12:05:06'),

date_part('day',timestamp'2016-07-08 12:05:06'),
date_part('hour',timestamp'2016-07-08 12:05:06'),

date_part('minute',timestamp'2016-07-08 12:05:06'),

date_part('second',timestamp'2016-07-08 12:05:06');

2016 | 7 | 8 | 12 | 5 | 6
date_part(text, interval) double precision 功能同上，只是第二个入参为时间间隔 select date_part('hour',interval'1 day 13:00:12'); 13
date_trunc(text, timestamp) timestamp

将时间戳截断成指定的精度，

指定精度后面的子域用0补充

select date_trunc('hour',

timestamp'2016-07-08 22:30:33');

 2016-07-08 22:00:00
date_trunc(text, interval) interval 功能同上，只是第二个入参为时间间隔 select date_trunc('hour',interval'1 year 2 mon 3 day 22:30:33'); 1 year 2 mons 3 days 22:00:00
extract(field from timestamp) double precision 功能同date_part(text, timestamp) select extract(hour from timestamp'2016-07-08 22:30:29'); 22
extract(field from interval) double precision 功能同date_part(text, interval) select extract(hour from interval'1 day 13:00:12'); 13
isfinite(date) boolean 测试是否为有穷日期 select isfinite(date'2016-07-08'),isfinite(date'infinity'); t,f
isfinite(timestamp) boolean 测试是否为有穷时间戳 select isfinite(timestamp'2016-07-08'); t
isfinite(interval) boolean 测试是否为有穷时间间隔 select isfinite(interval'1day 23:02:12'); t
justify_days(interval) interval 按照每月30天调整时间间隔 select justify_days(interval'1year 45days 23:00:00'); 1 year 1 mon 15 days 23:00:00
justify_hours(interval) interval 按照每天24小时调整时间间隔 select justify_hours(interval'1year 45days 343hour'); 1 year 59 days 07:00:00
justify_interval(interval) interval 同时使用justify_days(interval)和justify_hours(interval) select justify_interval(interval'1year 45days 343hour'); 1 year 1 mon 29 days 07:00:00
localtime time 当日时间 select localtime; 15:45:18.892224
localtimestamp timestamp 当日日期和时间 select localtimestamp; 2016-07-08 15:46:55.181583
make_date(year int, month int, day int) date 创建一个日期 select make_date(2016,7,8); 2016-07-08

make_interval(

years int DEFAULT 0,

months int DEFAULT 0,

weeks int DEFAULT 0,

days int DEFAULT 0,

hours int DEFAULT 0,

mins int DEFAULT 0,

secs double precision

DEFAULT 0.0)

 interval 创建一个时间间隔 select make_interval(1,hours=>3); 1 year 03:00:00

make_time(

hour int,

min int,

sec double precision)

 time 创建一个时间 select make_time(9,21,23); 09:21:23

make_timestamp(

year int, month int,

day int, hour int,

min int,

sec double precision)

 timestamp 创建一个时间戳 select make_timestamp(2016,7,8,22,55,23.5); 2016-07-08 22:55:23.5

make_timestamptz(year int,

month int,

day int, hour int,

min int, sec double precision, [ timezone text ])

 timestamp with time zone 创建一个带有时区的时间戳 select make_timestamptz(2016,7,8,22,55,23.5); 2016-07-08 22:55:23.5-07
now() timestamp with time zone 当前日期和时间 select now(); 2016-07-08 15:55:30.873537-07
statement_timestamp() timestamp with time zone 同now()  select statement_timestamp(); 2016-07-08 15:56:07.259956-07
timeofday() text

当前日期和时间，包含周几，

功能与clock_timestamp()类似

 select timeofday(); Fri Jul 08 15:57:51.277239 2016 PDT
transaction_timestamp() timestamp with time zone 事务开始时的时间戳 select transaction_timestamp(); 2016-07-08 16:01:25.007153-07
to_timestamp(double precision) timestamp with time zone

Convert Unix epoch

(seconds since 1970-01-01

00:00:00+00) to timestamp

 select to_timestamp(1284352323);

2010-09-12 21:32:03-07
pg_sleep(seconds double precision);  

当前会话休眠seconds秒

 select pg_sleep(5);  
pg_sleep_for(interval)   当前会话休眠多长时间的间隔 select pg_sleep_for('5 seconds');  
pg_sleep_until(timestamp with time zone)   当前会话休眠至什么时间点 select pg_sleep_until('2016-07-08 23:59:59');  

　

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