Syntax
------ 
UUID()
 
Description
----------- 
Returns a Universal Unique Identifier (UUID) generated
according to "DCE 1.1:
Remote Procedure Call" (Appendix A) CAE (Common
Applications Environment)
Specifications published by The Open Group in October
1997 
(Document Number C706).
 
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.
 
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.
 
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.
 
Examples
-------- 
SELECT UUID();
+--------------------------------------+
| UUID() |
+--------------------------------------+
| cd41294a-afb0-11df-bc9b-00241dd75637 |
+--------------------------------------+
 


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