How to generate a unique user ID?

Question

MySQL

How to create unique identifiers for users in MySQL database?

Answer 1

Hang AUTO_INCREMENT on the field and create a UNIQUE INDEX

Answer 2

What does "unique identifier" mean? primary key? :-)
If something is temporary (the session is there or something like that), then why is the UUID not suitable?

Answer 3

Depends on the application. For data binding inside the database, an auto-incrementing primary key is quite suitable, and for a URL or an intra-service address, you can use a login or, if the login is not suitable, generate a hash from the microtime, for example, and write it as an identifier.