INTERVAL

A duration or period of time. Written as INTERVAL 'value' UNIT where UNIT is one of DAY, MONTH, YEAR, HOUR, MINUTE, SECOND, or MICROSECOND.

Example

SELECT INTERVAL '7' DAY;

Casting

From	Example	Notes
to VARCHAR	`(INTERVAL '1' DAY)::VARCHAR`	Renders as an ISO-8601 duration by default, e.g. 'P1DT2H30M'
to VARCHAR (FORMAT)	`CAST(INTERVAL '1' DAY AS VARCHAR FORMAT 'DD HH24:MI:SS')`	Renders against an explicit SQL-style pattern; tokens (YYYY, MM, DD, HH24, MI, SS, FF) are reinterpreted as duration magnitudes (years/months-remainder/days/hours/minutes/seconds), not calendar fields

Arithmetic

Expression	Result Type	Description
`INTERVAL '1' DAY + INTERVAL '2' HOUR`	INTERVAL	Add two intervals
`date_col + INTERVAL '1' MONTH`	TIMESTAMP	Shift a date forward
`ts_col - INTERVAL '30' MINUTE`	TIMESTAMP	Shift a timestamp back

Comparisons

Can be compared (using =, <, >, etc.) with: INTERVAL.

Notes

Sub-month components (days, hours, minutes, seconds, microseconds) are stored as a microsecond count. Month and year components are stored separately and applied calendar-accurately during arithmetic. You cannot mix month-based and sub-month intervals in a single expression.

Limitations

There is no INTERVAL literal that combines months and days in one expression (e.g. '1 month 3 days' is not supported). Use separate additions.
CAST(literal AS INTERVAL) is rejected. INTERVAL can only be cast TO VARCHAR (see cast_to above); it cannot be cast FROM another type.
CAST ... FORMAT is not yet supported combined with TRY_CAST/SAFE_CAST.