Hey have coded all my site with mysqli. But most of the scripts I found from GitHub or other such sites are coded with mysql.
So, when am implementing that in my projects should i replace the mysql with mysqli or can i use both of them in my connection files and all other PHP files??
There is nothing stopping you from using both, but were I you I would choose one type of connection and go along with it. Mixing can be confusing not only for other people who read your code but also your future self.
You can use both of them. However this does not mean you should. You should not use 2 connections. For multiple reasons: