PostgreSQL 18 reference · UUID Functions

PostgreSQL GEN_RANDOM_UUID() Function

Generate a random version 4 UUID. Since PostgreSQL 18, uuidv4() is another name for it.

PostgreSQL 18 Since 13

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Syntax

gen_random_uuid()  |  uuidv4()

Return value

uuid.

Examples

A random UUID

SELECT length(gen_random_uuid()::text) AS chars, gen_random_uuid() <> gen_random_uuid() AS always_different;

Output

 chars | always_different
-------+------------------
    36 | t
(1 row)

Run this on your computer — see “Get Started” for setup.

As a column default

CREATE TABLE tickets (id uuid PRIMARY KEY DEFAULT gen_random_uuid(), title text);
INSERT INTO tickets (title) VALUES ('Printer jam'), ('VPN down');
SELECT count(DISTINCT id) AS unique_ids FROM tickets;