Repeater | User Search

Hello.
My situation is:
I have search form, in which the user will write a person name or city name.
Also, I have database with information “name, city, etc.”.
I connected repeater to the database.
I want the repeater to show only the elements which column comply to the user’s input.
How to do that?

And also, how to “get” the amount number of the complied elements?