support oracle build-in function: sys_guid

SYS_GUID is an Oracle function, similar to the UUID function in mariadb, the document link is:
https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sqlrf/SYS_GUID.html#GUID-761E36B4-32DA-497D-8829-3D4653381F9B

there are two difference between sys_guid and uuid in mariadb :

• output format: the output of sys_guid without '-' character.
• use different algorithms，please note the red font in the example
  1. Execute sys_guid multiple times in a session, and add 1 to the 12th byte of output each time
  2. execute sys_guid in different sessions, the 6~16 bytes and last 4 bytes of output are different

example for oracle sys_guid

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9C877B1264B49E05315500A0A222B

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9C877B1274B49E05315500A0A222B

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9C877B1284B49E05315500A0A222B

• start new session and execute sys_guid

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9CCEB9C1A4CBDE05315500A0AA3C2

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9CCEB9C1B4CBDE05315500A0AA3C2

SQL> SELECT SYS_GUID() FROM DUAL;

SYS_GUID()
--------------------------------
B4F9CCEB9C1C4CBDE05315500A0AA3C2

I have implemented SYS_ GUID, the behavior and algorithms are the same as UUID, but the output format is different.

MariaDB [(none)]> select sys_guid();

+----------------------------------+

| sys_guid()                       |

+----------------------------------+

| 4FE31C7B2F8E11EB8DAAA87EEAED1F75 |

+----------------------------------+

1 row in set (0.000 sec)

MariaDB [(none)]> select sys_guid();

+----------------------------------+

| sys_guid()                       |

+----------------------------------+

| 50DEAB622F8E11EB8DAAA87EEAED1F75 |

+----------------------------------+