This section describes functions and operators for examining and manipulating TIMESTAMP values.

Timestamp Operators

The table below shows the available mathematical operators for TIMESTAMP types.

Operator	Description	Example	Result
+	addition of an INTERVAL	TIMESTAMP '1992-03-22 01:02:03' + INTERVAL 5 DAY	1992-03-27 01:02:03
-	subtraction of TIMESTAMPs	TIMESTAMP '1992-03-27' - TIMESTAMP '1992-03-22'	5 days
-	subtraction of an INTERVAL	TIMESTAMP '1992-03-27 01:02:03' - INTERVAL 5 DAY	1992-03-22 01:02:03

Adding to or subtracting from infinite values produces the same infinite value.

Timestamp Functions

The table below shows the available scalar functions for TIMESTAMP types.

Function	Description	Example	Result
age(timestamp, timestamp)	Subtract arguments, resulting in the time difference between the two timestamps	age(TIMESTAMP '2001-04-10', TIMESTAMP '1992-09-20')	8 years 6 months 20 days
age(timestamp)	Subtract from current_date	age(TIMESTAMP '1992-09-20')	29 years 1 month 27 days 12:39:00.844
century(timestamp)	Extracts the century of a timestamp	century(TIMESTAMP '1992-03-22')	20
current_timestamp	Current date and time (start of current transaction)
date_diff(part, startdate, enddate)	The number of partition boundaries between the timestamps	date_diff('hour', TIMESTAMP '1992-09-30 23:59:59', TIMESTAMP '1992-10-01 01:58:00')	2
date_part(part, timestamp)	Get subfield (equivalent to extract)	date_part('minute', TIMESTAMP '1992-09-20 20:38:40')	38
date_sub(part, startdate, enddate)	The number of complete partitions between the timestamps	date_sub('hour', TIMESTAMP '1992-09-30 23:59:59', TIMESTAMP '1992-10-01 01:58:00')	1
date_trunc(part, timestamp)	Truncate to specified precision	date_trunc('hour', TIMESTAMP '1992-09-20 20:38:40')	1992-09-20 20:00:00
dayname(timestamp)	The (English) name of the weekday	dayname(TIMESTAMP '1992-03-22')	Sunday
epoch_ms(ms)	Converts ms since epoch to a timestamp	epoch_ms(701222400000)	1992-03-22 00:00:00
extract(field from timestamp)	Get subfield from a timestamp	extract('hour' FROM TIMESTAMP '1992-09-20 20:38:48')	20
greatest(timestamp, timestamp)	The later of two timestamps	greatest(TIMESTAMP '1992-09-20 20:38:48', TIMESTAMP '1992-03-22 01:02:03.1234')	1992-09-20 20:38:48
isfinite(timestamp)	Returns true if the timestamp is finite, false otherwise	isfinite(TIMESTAMP '1992-03-07')	true
isinf(timestamp)	Returns true if the timestamp is infinite, false otherwise	isinf(TIMESTAMP '-infinity')	true
last_day(timestamp)	The last day of the month.	last_day(TIMESTAMP '1992-03-22 01:02:03.1234')	1992-03-31
least(timestamp, timestamp)	The earlier of two timestamps	least(TIMESTAMP '1992-09-20 20:38:48', TIMESTAMP '1992-03-22 01:02:03.1234')	1992-03-22 01:02:03.1234
make_timestamp(bigint, bigint, bigint, bigint, bigint, double)	The timestamp for the given parts	make_timestamp(1992, 9, 20, 13, 34, 27.123456)	1992-09-20 13:34:27.123456
monthname(timestamp)	The (English) name of the month.	monthname(TIMESTAMP '1992-09-20')	September
now()	Current date and time (start of current transaction)
strftime(timestamp, format)	Converts timestamp to string according to the format string	strftime(timestamp '1992-01-01 20:38:40', '%a, %-d %B %Y - %I:%M:%S %p')	Wed, 1 January 1992 - 08:38:40 PM
strptime(text, format)	Converts string to timestamp according to the format string	strptime('Wed, 1 January 1992 - 08:38:40 PM', '%a, %-d %B %Y - %I:%M:%S %p')	1992-01-01 20:38:40
to_timestamp(sec)	Converts sec since epoch to a timestamp	to_timestamp(701222400)	1992-03-22 00:00:00

There are also dedicated extraction functions to get the subfields.

Functions applied to infinite dates will either return the same infinite dates (e.g, greatest) or NULL (e.g., date_part) depending on what “makes sense”. In general, if the function needs to examine the parts of the infinite date, the result will be NULL.

Timestamp Table Functions

The table below shows the available table functions for TIMESTAMP types.

Function	Description	Example
generate_series(timestamp, timestamp, interval)	Generate a table of timestamps in the closed range, stepping by the interval	generate_series(TIMESTAMP '2001-04-10', TIMESTAMP '2001-04-11', INTERVAL 30 MINUTE)
range(timestamp, timestamp, interval)	Generate a table of timestamps in the half open range, stepping by the interval	range(TIMESTAMP '2001-04-10', TIMESTAMP '2001-04-11', INTERVAL 30 MINUTE)

Infinite values are not allowed as table function bounds.