Try :)
$reviews_query_raw = "select r.reviews_id, rd.reviews_text, r.reviews_rating, r.date_added, p.products_id, pd.products_name, p.products_image, r.customers_name from " . TABLE_REVIEWS . " r, " . TABLE_REVIEWS_DESCRIPTION . " rd, " . TABLE_PRODUCTS . " p, " . TABLE_PRODUCTS_DESCRIPTION . " pd, " . TABLE_CATEGORIES . " c, " . TABLE_PRODUCTS_TO_CATEGORIES . " p2c where p.products_status = '1' and p.products_id = r.products_id and r.reviews_id = rd.reviews_id and p.products_id = pd.products_id and pd.language_id = '" . $languages_id . "' and rd.languages_id = '" . $languages_id . "' and p2c.categories_id = c.categories_id and r.approved = '1' order by r.reviews_id DESC";