I am thinking about encrypting some fields in MySQL database using MySQL's encryption functions. I can't find any good sources on how to properly implement it. Has anyone done this and have a good tutorial on this?

I would like to implement salt along with encryption key. I have found out that AES_ENCRYPT is better off with a fixed length key from mysql AES_ENCRYPT key length post. Has anyone written a MySQL function for key derivation algorithm?

EDIT:
For example, I have found a tutorial - Encrypt MySQL data using AES techniques, but it does not go into enough depth at all.