postgreSql——時區問題

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'

　　

　　

查看現在距1970-01-01 00:00:00 UTC 的秒數

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 值轉換回時間戳

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

　　

 

PostgreSQL的時間/日期函數使用

postgreSQL格式化時間的函數詳解

 

mysql轉為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;

　　

 

 

函數	返回類型	描述	示例	結果
age(timestamp, timestamp)	interval	計算兩個時間戳的時間間隔	select age(timestamp '2001-04-10', timestamp '1957-06-13');	43 years 9 mons 27 days
age(timestamp)	interval	計算current_date與入參時間戳的時間間隔	select age(timestamp '2016-07-07 12:00:00');	12:00:00
clock_timestamp()	timestamp with time zone	當前時間戳（語句執行時變化）	select clock_timestamp();	2016-07-08 15:14:04.197732-07
current_date	date	當前日期	select current_date;	2016-07-08
current_time	time with time zone	當前時間	select current_time;	15:15:56.394651-07
current_timestamp	timestamp with time zone	當前時間戳	select current_timestamp;	2016-07-08 15:16:50.485864-07
date_part(text, timestamp)	double precision	獲取時間戳中的某個子域，其中text可以為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，只是第二個入參為時間間隔	select date_part('hour',interval'1 day 13:00:12');	13
date_trunc(text, timestamp)	timestamp	將時間戳截斷成指定的精度， 指定精度后面的子域用0補充	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，只是第二個入參為時間間隔	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	測試是否為有窮日期	select isfinite(date'2016-07-08'),isfinite(date'infinity');	t,f
isfinite(timestamp)	boolean	測試是否為有窮時間戳	select isfinite(timestamp'2016-07-08');	t
isfinite(interval)	boolean	測試是否為有窮時間間隔	select isfinite(interval'1day 23:02:12');	t
justify_days(interval)	interval	按照每月30天調整時間間隔	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小時調整時間間隔	select justify_hours(interval'1year 45days 343hour');	1 year 59 days 07:00:00
justify_interval(interval)	interval	同時使用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	當日時間	select localtime;	15:45:18.892224
localtimestamp	timestamp	當日日期和時間	select localtimestamp;	2016-07-08 15:46:55.181583
make_date(year int, month int, day int)	date	創建一個日期	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	創建一個時間間隔	select make_interval(1,hours=>3);	1 year 03:00:00
make_time( hour int,  min int,  sec double precision)	time	創建一個時間	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	創建一個時間戳	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	創建一個帶有時區的時間戳	select make_timestamptz(2016,7,8,22,55,23.5);	2016-07-08 22:55:23.5-07
now()	timestamp with time zone	當前日期和時間	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	當前日期和時間，包含周幾， 功能與clock_timestamp()類似	select timeofday();	Fri Jul 08 15:57:51.277239 2016 PDT
transaction_timestamp()	timestamp with time zone	事務開始時的時間戳	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);		當前會話休眠seconds秒	select pg_sleep(5);
pg_sleep_for(interval)		當前會話休眠多長時間的間隔	select pg_sleep_for('5 seconds');
pg_sleep_until(timestamp with time zone)		當前會話休眠至什么時間點	select pg_sleep_until('2016-07-08 23:59:59');