I want to find the int value of the latest id from my blog post database or use the one provided by GET. If I manually enter the GET into the URL, when I try `echo 'current id='.$current_id;`, the GET will echo the number but if there is no GET variable, it will echo `current id=SELECT max(id) FROM posts;`

```
if(isset($_GET['id'])){
  $current_id = $_GET['id'];
  }
else{
  $current_id = 'SELECT max(id) FROM posts';
}

```

Why does PHP think this is a string?