Syntax
------

UUID()

Description
-----------

Returns a Universally Unique Identifier (UUID).

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() results are intended to be unique, but cannot always be relied upon to
unpredictable and unguessable, so should not be relied upon for these purposes.

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

* The first three numbers are generated from a timestamp.
* The fourth number preserves temporal uniqueness in case the timestamp value
 loses monotonicity (for example, due to daylight saving time).
* The fifth number is an IEEE 802 node number that provides spatial uniqueness.
 A random number is substituted if the latter is not available (for example,
 because the host computer has no Ethernet card, or we do not know how to find
 the hardware address of an interface on your operating system). In this case,
 spatial uniqueness cannot be guaranteed. Nevertheless, a collision should
 have very low probability.

Currently, the MAC address of an interface is taken into account only on
FreeBSD and Linux. On other operating systems, MariaDB uses a randomly
generated 48-bit number.

Statements using the UUID() function are not safe for replication.

The results are generated according to the "DCE 1.1:Remote Procedure Call"
(Appendix A) CAE (Common Applications Environment) Specifications published by
The Open Group in October 1997 (Document Number C706).

Examples
--------

SELECT UUID();
+--------------------------------------+
| UUID()                               |
+--------------------------------------+
| cd41294a-afb0-11df-bc9b-00241dd75637 |
+--------------------------------------+

URL: https://mariadb.com/kb/en/uuid/