How to apply bindValue method in LIMIT clause?

Here is a snapshot of my code:

$fetchPictures = $PDO->prepare("SELECT * 
    FROM pictures 
    WHERE album = :albumId 
    ORDER BY id ASC 
    LIMIT :skip, :max");

$fetchPictures->bindValue(':albumId', $_GET['albumid'], PDO::PARAM_INT);

if(isset($_GET['skip'])) {
    $fetchPictures->bindValue(':skip', trim($_GET['skip']), PDO::PARAM_INT);    
} else {
    $fetchPictures->bindValue(':skip', 0, PDO::PARAM_INT);  
}

$fetchPictures->bindValue(':max', $max, PDO::PARAM_INT);
$fetchPictures->execute() or die(print_r($fetchPictures->errorInfo()));
$pictures = $fetchPictures->fetchAll(PDO::FETCH_ASSOC);

I get

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''15', 15' at line 1

It seems that PDO is adding single quotes to my variables in the LIMIT part of the SQL code. I looked it up I found this bug which I think is related: http://bugs.php.net/bug.php?id=44639

Is that what I'm looking at? This bug has been opened since April 2008! What are we supposed to do in the meantime?

I need to build some pagination, and need to make sure the data is clean, sql injection-safe, before sending the sql statement.

Solution 1:

I remember having this problem before. Cast the value to an integer before passing it to the bind function. I think this solves it.

$fetchPictures->bindValue(':skip', (int) trim($_GET['skip']), PDO::PARAM_INT);

Solution 2:

The simplest solution would be to switch the emulation mode off. You can do it by simply adding the following line

$PDO->setAttribute( PDO::ATTR_EMULATE_PREPARES, false );

Also, this mode can be set as a constructor parameter when creating a PDO connection. It could be a better solution as some report their driver doesn't support the setAttribute() function.

It will not only solve your problem with binding, but also let you send values directly into execute(), which will make your code dramatically shorter. Assuming the emulation mode has been already set, the whole affair will take as much as half a dozen lines of code

$skip = isset($_GET['skip']) ? (int)trim($_GET['skip']) : 0;
$sql  = "SELECT * FROM pictures WHERE album = ? ORDER BY id LIMIT ?, ?";
$stmt  = $PDO->prepare($sql);
$stmt->execute([$_GET['albumid'], $skip, $max]);
$pictures = $stmt->fetchAll(PDO::FETCH_ASSOC);