Is there a way to demonstrate SQL injection with mysqli?

Question

I want to make a quick and easy demonstration about how SQL injection work. And I\'ve solved some of my problems. I have a table with random usernames, passwords and emails in,

Answer 1

Did you try something like this ?

'(here put something);

in this way you are going to close the query with ' and add other stuff to it, when you add ; everything else is going to be discarded