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SQL Server: datatype uniqueidentifier

The data type uniqueidentifier stores 16-bit GUIDs.

Creation of values for uniqueidentifier

A uniqueidentifier can be created with

newid()
newsequentialid() (however in a default constraint of a table column only)
by assigning a varchar representation of a GUID to a uniqueidentifer

declare
   @uid_1   uniqueidentifier,
   @uid_2   uniqueidentifier;

set @uid_1 = newid()          ; -- compliant with RFC 4122
set @uid_2 = '01234567-89ab-cdef-0123-456789abcdef';

print('uid_1 =  ' + convert(varchar(255), @uid_1));
print('uid_2 =  ' + convert(varchar(255), @uid_2));

Github repository about-MSSQL, path: /t-sql/data-types/uniqueidentifier/create.sql

See also

SQL Server: Data types