Date/Time Types

Date Inputs

Date and time input is accepted in almost any reasonable formats, including ISO 8601, SQL-compatible, and traditional Postgres. The system allows you to customize the sequence of day, month, and year in the date input. Set the DateStyle parameter to MDY to select month-day-year interpretation, DMY to select day-month-year interpretation, or YMD to select year-month-day interpretation.

Remember that any date or time literal input needs to be enclosed with single quotation marks (''), and the syntax is as follows:

type [ ( p ) ] 'value'

The p that can be selected in the precision statement is an integer, indicating the number of fractional digits in the seconds column. Table 2 shows the input formats of the date type.

Example:

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-- Create a table.
gaussdb=# CREATE TABLE date_type_tab(coll date);

-- Insert data.
gaussdb=# INSERT INTO date_type_tab VALUES (date '12-10-2010');

-- View data.
gaussdb=# SELECT * FROM date_type_tab;
        coll         
---------------------
 2010-12-10(1 row)

-- View the date format.
gaussdb=# SHOW datestyle;
 DateStyle 
-----------
 ISO, MDY
(1 row)

-- Set the date format.
gaussdb=# SET datestyle='YMD';
SET

-- Insert data.
gaussdb=# INSERT INTO date_type_tab VALUES(date '2010-12-11');

-- View data.
gaussdb=# SELECT * FROM date_type_tab;
        coll         
---------------------
 2010-12-10 2010-12-11(2 rows)

-- Delete a table.
gaussdb=# DROP TABLE date_type_tab;

Time

The time-of-day types are TIME [(p)] [WITHOUT TIME ZONE] and TIME [(p)] [WITH TIME ZONE]. TIME alone is equivalent to TIME WITHOUT TIME ZONE.

If a time zone is specified in the input for TIME WITHOUT TIME ZONE, it is silently ignored.

For details about the time input types, see Table 4. For details about time zone input types, see Table 3.

Example:

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gaussdb=# SELECT time '04:05:06';
   time   
----------
 04:05:06
(1 row)

gaussdb=# SELECT time '04:05:06 PST';
   time   
----------
 04:05:06
(1 row)

gaussdb=# SELECT time with time zone '04:05:06 PST';
   timetz    
-------------
 04:05:06-08
(1 row)

Special Values

The special values supported by GaussDB are converted to common date/time values when being read. For details, see Table 5.

Example:

-- Create a table.
gaussdb=# CREATE TABLE realtime_type_special(col1 varchar(20), col2 date, col3 timestamp, col4 time);

-- Insert data.
gaussdb=# INSERT INTO realtime_type_special VALUES('epoch', 'epoch', 'epoch', NULL);
gaussdb=# INSERT INTO realtime_type_special VALUES('now', 'now', 'now', 'now');
gaussdb=# INSERT INTO realtime_type_special VALUES('today', 'today', 'today', NULL);
gaussdb=# INSERT INTO realtime_type_special VALUES('tomorrow', 'tomorrow', 'tomorrow', NULL);
gaussdb=# INSERT INTO realtime_type_special VALUES('yesterday', 'yesterday', 'yesterday', NULL);

-- View data.
gaussdb=# SELECT * FROM realtime_type_special;
   col1    |        col2         |            col3            |      col4
-----------+---------------------+----------------------------+-----------------
 epoch     | 1970-01-01 00:00:00 | 1970-01-01 00:00:00        |
 now       | 2023-02-27 11:38:13 | 2023-02-27 11:38:13.032815 | 11:38:13.032815
 today     | 2023-02-27 00:00:00 | 2023-02-27 00:00:00        |
 tomorrow  | 2023-02-28 00:00:00 | 2023-02-28 00:00:00        |
 yesterday | 2023-02-26 00:00:00 | 2023-02-26 00:00:00        |
(5 rows)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 < 'infinity';
   col1    |        col2         |            col3            |      col4
-----------+---------------------+----------------------------+-----------------
 epoch     | 1970-01-01 00:00:00 | 1970-01-01 00:00:00        |
 now       | 2023-02-27 11:38:13 | 2023-02-27 11:38:13.032815 | 11:38:13.032815
 today     | 2023-02-27 00:00:00 | 2023-02-27 00:00:00        |
 tomorrow  | 2023-02-28 00:00:00 | 2023-02-28 00:00:00        |
 yesterday | 2023-02-26 00:00:00 | 2023-02-26 00:00:00        |
(5 rows)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 > '-infinity';
   col1    |        col2         |            col3            |      col4
-----------+---------------------+----------------------------+-----------------
 epoch     | 1970-01-01 00:00:00 | 1970-01-01 00:00:00        |
 now       | 2023-02-27 11:38:13 | 2023-02-27 11:38:13.032815 | 11:38:13.032815
 today     | 2023-02-27 00:00:00 | 2023-02-27 00:00:00        |
 tomorrow  | 2023-02-28 00:00:00 | 2023-02-28 00:00:00        |
 yesterday | 2023-02-26 00:00:00 | 2023-02-26 00:00:00        |
(5 rows)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 > 'now';
   col1   |        col2         |        col3         | col4
----------+---------------------+---------------------+------
 tomorrow | 2023-02-28 00:00:00 | 2023-02-28 00:00:00 |
(1 row)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 = 'today';
 col1  |        col2         |        col3         | col4
-------+---------------------+---------------------+------
 today | 2023-02-27 00:00:00 | 2023-02-27 00:00:00 |
(1 row)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 = 'tomorrow';
   col1   |        col2         |        col3         | col4
----------+---------------------+---------------------+------
 tomorrow | 2023-02-28 00:00:00 | 2023-02-28 00:00:00 |
(1 row)

gaussdb=# SELECT * FROM realtime_type_special WHERE col3 > 'yesterday';
   col1   |        col2         |            col3            |      col4
----------+---------------------+----------------------------+-----------------
 now      | 2023-02-27 11:38:13 | 2023-02-27 11:38:13.032815 | 11:38:13.032815
 today    | 2023-02-27 00:00:00 | 2023-02-27 00:00:00        |
 tomorrow | 2023-02-28 00:00:00 | 2023-02-28 00:00:00        |
(3 rows)

gaussdb=# SELECT TIME 'allballs';
   time
----------
 00:00:00
(1 row)

-- Delete a table.
gaussdb=# DROP TABLE realtime_type_special;

Interval Input

The input of reltime can be any valid interval in text format. It can be a number (negative numbers and decimals are also allowed) or a specific time, which must be in SQL standard format, ISO-8601 format, or POSTGRES format. In addition, the text input needs to be enclosed with single quotation marks ('').

For details about interval input, see Table 6.

Example:

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-- Create a table.
gaussdb=# CREATE TABLE reltime_type_tab(col1 character(30), col2 reltime);

-- Insert data.
gaussdb=# INSERT INTO reltime_type_tab VALUES ('90', '90');
gaussdb=# INSERT INTO reltime_type_tab VALUES ('-366', '-366');
gaussdb=# INSERT INTO reltime_type_tab VALUES ('1975.25', '1975.25');
gaussdb=# INSERT INTO reltime_type_tab VALUES ('-2 YEARS +5 MONTHS 10 DAYS', '-2 YEARS +5 MONTHS 10 DAYS');
gaussdb=# INSERT INTO reltime_type_tab VALUES ('30 DAYS 12:00:00', '30 DAYS 12:00:00');
gaussdb=# INSERT INTO reltime_type_tab VALUES ('P-1.1Y10M', 'P-1.1Y10M');

-- View data.
gaussdb=# SELECT * FROM reltime_type_tab;
              col1              |                col2                 
--------------------------------+-------------------------------------
 90                             | 3 mons
 -366                           | -1 years -18:00:00
 1975.25                        | 5 years 4 mons 29 days
 -2 YEARS +5 MONTHS 10 DAYS     | -1 years -6 mons -25 days -06:00:00
 30 DAYS 12:00:00               | 1 mon 12:00:00
 P-1.1Y10M                      | -3 mons -5 days -06:00:00
(6 rows)

-- Delete a table.
gaussdb=# DROP TABLE reltime_type_tab;