Call to undefined function query()

[tony09uk]

I am getting the following error message:

Call to undefined function query()

My code is this:

if(!isset($_GET['id'])){
header('Location: index.php');
exit();
} else {
$id = $_GET['id'];
}

$db = new mysqli('localhost', 'root', 'penbird098', 'blog') or die('error with connection');

if(!is_numeric($id)){
header('Location: blogIndex.php');
}

$sql = query("SELECT title, body FROM posts WHERE posts_id='$id'");
$query = $db->query($sql);
if($query !=1){
header('Location: index.php');
exit();
}

I know from the error message it is something to do with:
$query = $db->query($sql);
But I can't figure out what. I have done a few searches on google and not really found anything that is helpful to me. Can someone please provide me with a bit of guidance.

Many thanks

Tony

[tony09uk]

well, it seems I'd been staring at the problem so long I couldn't see the wood for the trees.

$sql = query("SELECT title, body FROM posts WHERE posts_id='$id'");

was wrong, I didnt need query()