PostgreSQL includes one function to generate a UUID:
This function returns a version 4 (random) UUID. This is the most commonly used type of UUID and is appropriate for most applications.
The uuid-ossp module provides additional functions that implement other standard algorithms for generating UUIDs.
PostgreSQL also provides the usual comparison operators shown in Table 9.1 for UUIDs.
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.