Interval

Overview

The Interval data type represents periods between dates or times, which can be precisely calculated and expressed through various units. Those can be combined and include additional options for different interval calculations.

In this doc, you’ll find more about the interval syntax, learn what are supported units and abbreviations, browse through examples and finally find out how to extract data from intervals.

Syntax

The syntax for specifying an interval is as follows:

SELECT INTERVAL 'quantity unit [quantity unit...] [direction]' [OPTION]

Parameters Description

Parameter	Description
quantity	The value representing the number of units
unit	- Year, month, day, hour, minute, etc. - Abbreviations, short forms and dash format is supported - Plural forms are also acceptable (e.g. months, days, weeks)
direction	An optional parameter: ago or empty string
OPTION	Additional options when parsing interval

Supported Units and Abbreviations

Unit	Abbreviations
Millennium	-
Century	-
Decade	-
Year	y, yr, yrs
Month	-
Week	-
Day	d
Hour	h, hr, hrs
Minute	min, mins, m
Second	s, sec, secs
Millisecond	ms
Microsecond	-

Options for Interval Parsing

• YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
• YEAR TO MONTH, DAY TO HOUR, DAY TO MINUTE, DAY TO SECOND, HOUR TO MINUTE, HOUR TO SECOND, MINUTE TO SECOND

Examples

Select Interval With Multiple Units

In this example, we’ll calculate the interval by combining multiple units of time.

SELECT INTERVAL '5 years 4 months 2 weeks 3 days 5 hours 10 minutes 25 seconds' as "Interval";

            Interval             
---------------------------------
 5 years 4 mons 17 days 05:10:25
(1 row)

Using Abbreviations

This example shows how to use abbreviated units for time intervals.

SELECT INTERVAL '10 yr 8 months 2 weeks 6 days 5 hrs 10 min 20 s as "Interval";

             Interval             
----------------------------------
 10 years 8 mons 20 days 05:10:20
(1 row)

Using Dash Format

Here you’ll find out how to use the dash format for specifying intervals.

SELECT INTERVAL '1-2 3 DAYS 04:05:06.070809' as "Interval";

               Interval               
--------------------------------------
 1 year 2 mons 3 days 04:05:06.070809
(1 row)

Parsing Intervals Using Specific Units

By running the code below, the output will show everything up to minutes and ignore seconds and miliseconds.

SELECT INTERVAL '1-2 5 DAYS 07:08:06.040809' MINUTE as "Interval";

           Interval            
-------------------------------
 1 year 2 mons 5 days 07:08:00
(1 row)

Displaying Specific Range Only

Executing the query below will result only years and months being displayed excluding days, hours, minutes, and seconds from the input.

SELECT INTERVAL '2-4 5 DAYS 04:05:06.070809' YEAR TO MONTH as "Interval";

    Interval    
----------------
 2 years 4 mons
(1 row)

Extracting Data From Interval

In order to extract the interval numbers from the timestamp, you can use the EXTRACT() function the following way:

SELECT EXTRACT (field FROM interval)

• field: supports time units, such as YEAR, MONTH, DAY, HOUR, etc.
• interval: specified timestamp.

SELECT EXTRACT (MINUTE
FROM INTERVAL '2 hours 30 minutes');

As the output of the above query, only the minutes part will be returned.

   extract    
------------
        30
(1 row)

If you query a field that is not specified in the timestamp, you will get 0 as an output.