EXTRACT #6 of #100PostgreSQLFunctions

This post is a part of the project #100PostgreSQLFunctions, which aims to explain the meaning of 100 PostgreSQL functions and how to use them. For the full list of functions click here.

EXTRACT is a function to retrieve subfields of a value, which has to be one of the following datatypes: date, timestamp or interval. By parenthesis, we need to specify the subfield to extract, and from which value we want to get it.

Examples:

SELECT
    EXTRACT(month from '2/20/2019'::date);

 date_part
-----------
         2
(1 row)


SELECT
    EXTRACT(second from '2/20/2019 12:5:34'::timestamp);

 date_part
-----------
        34
(1 row)


SELECT
    EXTRACT(day from '6 years 5 months 4 days'::interval);

 date_part
-----------
         4
(1 row)