How can I do private chat in my website?

Question

So user A could send message to user B, not to everyone. Please any idea or suggestions, or what I should learn for that. I know ajax php mysql, but basics . In YouTube no one video who teaches this, all tutorial only about simple web chat, not private. Please help

Answer 1

Add an Id for B then in the message from A specify the B Id so that B can access to message that has it's id