Description:
------------
---
From manual page: http://www.php.net/pdo.prepare
---

The manual says "You cannot use a named parameter marker of the same name twice in a prepared statement", however this is not completely true. If PDO::ATTR_EMULATE_PREPARES is set to true, you *can* re-use the same parameter marker more than once. I'm not sure if this is a bug with the docs or a bug with PDO.

Test script:
---------------
The following worked just fine for me by default (I'm assuming prepared statements were being emulated):

<?php
$stmt = $dbh->prepare("
    SELECT tour_photo_id, name, `desc` FROM
    (
        SELECT tour_photo_id, tours_i18n.name, `desc` FROM
        tour_photos
        LEFT JOIN tour_photos_i18n ON tour_photos.id = tour_photos_i18n.tour_photo_id
        LEFT JOIN tours ON tour_photos.tour_id = tours.id
        LEFT JOIN tours_i18n ON tours.id = tours_i18n.tour_id
        WHERE tour_photos.id IN (".implode(',', $banner_img_ids).")
        AND tours_i18n. lang_id = :lang_id
        AND tour_photos_i18n.lang_id = :lang_id

        UNION

        SELECT tour_photo_id, tours_i18n.name, `desc` FROM
        tour_photos
        LEFT JOIN tour_photos_i18n ON tour_photos.id = tour_photos_i18n.tour_photo_id
        LEFT JOIN tours ON tour_photos.tour_id = tours.id
        LEFT JOIN tours_i18n ON tours.id = tours_i18n.tour_id
        WHERE tour_photos.id IN (".implode(',', $banner_img_ids).")
        AND tours_i18n. lang_id = :en_lang_id
        AND tour_photos_i18n.lang_id = :en_lang_id
    ) a
    GROUP BY tour_photo_id
    ORDER BY FIELD(tour_photo_id, ".implode(',', $banner_img_ids).")
    ");
$stmt->bindValue(':lang_id', $lang_id);
$stmt->bindValue(':en_lang_id', $en_lang_id);
$stmt->execute();
?>

Note, both :lang_id and :en_lang_id are used more than once.

However when I set PDO::ATTR_EMULATE_PREPARES to false, I get 'SQLSTATE[HY093]: Invalid parameter number'.