Destroying sessions in PHP

I was researching about logout functions in php and I saw examples like:

if(isset($_SESSION)) { 
     unset($_SESSION['minhaSessao']); //repetir para cada sessao
     session_unregister(); 
     session_destroy(); 
}

I wanted to know if there is any way to clear all the active sessions of my application without having to set one by one repeatedly.

This code is redundant, only session_destroy(); alone solves the case. You do not need if , nor other commands.

link

create a file with only session_destroy(); and use logoff, it is enough to break all php sessions