Echo values in PHP

I need a little help with achieving a project. I am creating a user profile and will like to display two values randomly from a database column without repeating each one amongst all the users using php.

For instance i have (column 1) which contains all the alphabets from A - Z. And i have the following users (mike, andrew, felix)

If "A" and "J" displays on mikes profile, they shouldn't repeat again. Andrew and Felix should have different alphabets

Thank you for assisting