Examples of interval literals without qualifier syntax - Amazon Redshift
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# Examples of interval literals without qualifier syntax

###### Note

The following examples demonstrate using an interval literal without a `YEAR TO MONTH` or `DAY TO SECOND` qualifier. For information about using the recommended interval literal with a qualifier, see Interval data types and literals.

Use an interval literal to identify specific periods of time, such as `12 hours` or `6 months`. You can use these interval literals in conditions and calculations that involve datetime expressions.

An interval literal is expressed as a combination of the INTERVAL keyword with a numeric quantity and a supported date part, for example ```INTERVAL '7 days'``` or `INTERVAL '59 minutes'`. You can connect several quantities and units to form a more precise interval, for example: `INTERVAL '7 days, 3 hours, 59 minutes'`. Abbreviations and plurals of each unit are also supported; for example: `5 s`, ```5 second```, and `5 seconds` are equivalent intervals.

If you don't specify a date part, the interval value represents seconds. You can specify the quantity value as a fraction (for example: `0.5 days`).

The following examples show a series of calculations with different interval values.

The following adds 1 second to the specified date.

``````select caldate + interval '1 second' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2008-12-31 00:00:01
(1 row)``````

The following adds 1 minute to the specified date.

``````select caldate + interval '1 minute' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2008-12-31 00:01:00
(1 row)``````

The following adds 3 hours and 35 minutes to the specified date.

``````select caldate + interval '3 hours, 35 minutes' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2008-12-31 03:35:00
(1 row)``````

The following adds 52 weeks to the specified date.

``````select caldate + interval '52 weeks' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2009-12-30 00:00:00
(1 row)``````

The following adds 1 week, 1 hour, 1 minute, and 1 second to the specified date.

``````select caldate + interval '1w, 1h, 1m, 1s' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2009-01-07 01:01:01
(1 row)``````

The following adds 12 hours (half a day) to the specified date.

``````select caldate + interval '0.5 days' as dateplus from date
where caldate='12-31-2008';
dateplus
---------------------
2008-12-31 12:00:00
(1 row)``````

The following subtracts 4 months from February 15, 2023 and the result is October 15, 2022.

``````select date '2023-02-15' - interval '4 months';

?column?
---------------------
2022-10-15 00:00:00
``````

The following subtracts 4 months from March 31, 2023 and the result is November 30, 2022. The calculation considers the number of days in a month.

``````select date '2023-03-31' - interval '4 months';

?column?
---------------------
2022-11-30 00:00:00
``````