if(!isset($_GET['id']) with to different options with the same variable

Question

I have this code: it works fine

Answer 1

Use in_array and add all the values you want to check against into the array:

if(!isset($_GET['id']) || !in_array($_GET['id'], array('1000', '2000'))){
    echo 'not 1k or 2 k';
} else {
    echo 'is 1k or 2k';
}

Functional example: https://3v4l.org/Q2uao