html purifier library usage concept

问题

Hi
I am at prototype stage with my site. I read the html purifier main page and questions about this library in this site but I am still not clear with the issue on my mind. Can you guide me please?
Thanks, BR

My Understanding:

From the docs I have read, I understood that the best I can do is:

1. to use mysqli_real_escape_string while inputting untrusted data into my mysql database
2. to use html purifier library while outputting data from mysql database to sscreen as html

My Questions

Q1) Does my understanding makes sense?

Q2) Do I still another sanitization method while inputting data into mysql or outputting from mysql to screen? I think these 2 methods are pretty enough for an amateur but can you please share your idea.

来源：https://stackoverflow.com/questions/14959707/html-purifier-library-usage-concept