In PostgreSQL, we can use the + operator to add one or more hours to a time value.

By “time” value, this could be an actual time value, a timestamp, or an interval. We can also add hours to a date value or a date and time combination.

Example

We can specify intervals when adding to dates and times. For example, we can use hour or hours to add one or more hours:

SELECT time '08:35' + interval '1 hour';

Result:

09:35:00

Plural

And in plural form:

SELECT time '08:35' + interval '2 hours';

Result:

10:35:00

Timestamps

And here it is with a timestamp value:

SELECT timestamp '2030-01-20 08:35' + interval '2 hours';

Result:

2030-01-20 10:35:00

Intervals

We can also add hours to an interval:

SELECT interval '23 hours' + interval '2 hours';

Result:

25:00:00

Dates

We can even add hours to a date value:

SELECT date '2030-01-20' + interval '3 hours';

Result:

2030-01-20 03:00:00

The result is a timestamp value.

Date & Time Values Combined

We can also add a date and time value together, and add hours to that:

SELECT date '2030-01-20' + time '02:35' + interval '3 hours';

Result:

2030-01-20 05:35:00

Specified in Minutes

Another way to do it is to specify the equivalent number in minutes:

SELECT time '15:45' + interval '60 minutes';

Result:

16:45:00

When doing this, we don’t need to be exactly on the hour. For example, we could add more than one hour, but less than two:

SELECT time '15:45' + interval '90 minutes';

Result:

17:15:00

Negative Values

It’s possible to perform date arithmetic with negative values. If we use a negative value with the + operator, then the specified number of hours will be subtracted from the input date/time. But if we use it with the - operator, then it will be added to the input date/time.

Example:

SELECT time '03:00' - interval '-2 hours';

Result:

05:00:00