ORACLE
function select sys_guid() from dual
select sys_guid() from dual
DB2
function RAND()
function GENERATE_UNIQUE() CHAR(13) FOR BIT DATA
SELECT concat (hex (RAND ()), hex (RAND ())) a FROM SYSIBM.SYSDUMMY1 - 32
select HEX(GENERATE_UNIQUE()) from sysibm.sysdummy1; - 26 number char
SQL server
NEWID() with separator '-'
select replace(NEWID(),'-','')AS A