On which language we should have command to become a Hacker

Answer 1

Hacking is not about languages, it's about knowledge of security systems, their weaknesses and technologies they use to work on. In other words, not every professional hacker is a good programmer and not every professional programmer is a good hacker.

Answer 2

For example, if you want to learn about how to exploit SQL injections for unauthorized retrieving data from secured databases you do not have to learn any programming languages at all but you should have a strong knowledge of SQL language that is not even a programming language in fact.