Interval literals

Following are rules for working with interval literals that are supported by AWS Clean Rooms.

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

An interval 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).

Examples

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

The following example 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 example 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 example 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 example 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 example 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 example 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 example 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 example 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