# UUID\_v4

{% hint style="info" %}
`UUID_v4` is available from MariaDB [11.7](https://app.gitbook.com/s/aEnK0ZXmUbJzqQrTjFyb/community-server/old-releases/11.7/what-is-mariadb-117).
{% endhint %}

It is possible to generate UUIDv4 and UUIDv7, in addition to UUIDv1.

## Syntax

```sql
UUID_v4()
```

## Description

Returns a Universally Unique Identifier (UUID) version 4. To generate a version 1 UUID, see the [UUID](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/uuid) function. To generate a version 7 UUID, see [UUIDv7](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/uuid_v7).

A UUID is designed as a number that is globally unique in space and time. Two calls to `UUID()` are expected to generate two different values, even if these calls are performed on two separate computers that are not connected to each other.

UUID\_v4() results are intended to be unique, but cannot always be relied upon to be unpredictable and unguessable.

A UUID is a 128-bit number represented by a utf8 string of five hexadecimal numbers in `aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee` format.

Statements using the UUID\_v4() function are not [safe for statement-based replication](https://mariadb.com/docs/server/ha-and-performance/standard-replication/unsafe-statements-for-statement-based-replication).

## Examples

```sql
SELECT UUID(),UUID_v4(),UUID_v7()\G 
*************************** 1. row ***************************
  UUID(): 63ae8c92-799a-11ef-98b2-f859713e4be4
UUID_v4(): a2443495-1b94-415b-b6fa-fe8e79ba4812
UUID_v7(): 01921e85-f198-7490-9b89-7dd0d468543b

CREATE TABLE t1 (a INT PRIMARY KEY NOT NULL, u UUID DEFAULT UUID_v4(), UNIQUE KEY(u));
```

## See Also

* [UUID()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/uuid) v1
* [UUID\_v7()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/uuid_v7)
* [UUID\_SHORT()](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/uuid_short) - Return short (64 bit) Universal Unique Identifier
* [SYS\_GUID](https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/miscellaneous-functions/sys_guid) - UUID without the `-` character for Oracle compatibility
* [UUID data type](https://mariadb.com/docs/server/reference/data-types/string-data-types/uuid-data-type)
* [MDEV-11339](https://jira.mariadb.org/browse/MDEV-11339) (Support UUID v4 generation)
* [MDEV-32637](https://jira.mariadb.org/browse/MDEV-32637) (Implement native UUID7 function)

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

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