I have defined a function in my Navigation model that executes a query, and I was wondering if there's a more "Zendy" way of generating/executing the query. The query I'm using was proposed by Bill Karwin on another thread here for setting arbitrary record order. I tried using a prepared statement, but the values in the SIGN() function got quoted.

I'm using the PDO adapter for MySQL.

/**
 *
 */
public function setPosition($parentId, $oldPosition, $newPosition)
{
    $parentId = intval($parentId);
    $oldPosition = intval($oldPosition);
    $newPosition = intval($newPosition);
    $this->getAdapter()->query("
        UPDATE `navigation`
        SET `position` = CASE `position`
            WHEN $oldPosition THEN $newPosition
            ELSE `position` + SIGN($oldPosition - $newPosition)
            END
        WHERE `parent_id` = $parentId
        AND `position` BETWEEN LEAST($oldPosition, $newPosition)
            AND GREATEST($oldPosition, $newPosition)
    ");
    return $this;
}