fetching json or mysql?

Question

MySQL

Let's say the user enters a letter and a list of cities is displayed via ajax. How will the selection be faster - through json or mysql?

Answer 1

It will be faster through MySQL, since you can immediately make a search query for the letter entered by the user, and if you use json, you will need to open the entire file and then search.

Answer 2

json is a data interchange format.
mysql is a database management system.
How can you compare them?)