check if variable empty

Question

if ($user_id == NULL || $user_name == NULL || $user_logged == NULL) {
    $user_id = \'-1\';
    $user_name = NULL;
    $user_logged = NULL;
}
if ($user_admin == NUL         


        

Answer 1

here i have explained how the empty function and isset works please use the one that is appropriate also you can use is_null function also