how to use in case in validate in larave? code example

Example 1: valdidate laravel if falid

$validator = Validator::make($request->all(), [
    'name' => 'required|min:2|max:255'
]);

if ($validator->fails()) {
    return view('view_name');
} else {
    return view('view_name');
}

Example 2: validate field for existing client laravel

unique:users,username,id,1 // table, field, idcolumn, value to ignore