$sqlx=sprintf("Select * from quartos");
$resx=mysqli_query($ligacao,$sqlx);

<?php
    while($regx=mysqli_fetch_array($resx)){
    ?>
    <div class="room-box">
        <form method="post">
        <div class="col-md-5 room-img" data-bg-img="<?php echo $regx['nome_doc'];?>">
            <div class="select-room-box">
                <a href="booking-2.php?id=<?php echo $regx['id'];?>">Selecione Este Quarto</a>
            </div>
        </div>
        <div class="r-sec col-md-7">
            <div class="title-box">
                <div class="title"><?php echo $regx['nome'];?></div>
                    <div class="price">
                        <div class="title">Preço :</div>
                        <div class="value"><?php echo $regx['preco'];?>€</div>
                    </div>
                    <a href="#price-break-down-1" class="price-breakdown"><i class="fa fa-caret-right"></i>Lista de Preços</a>
                    <div id="price-break-down-1" class="price-breakdown-popup mfp-hide">
                        <table>
                            <tr>
                                <td>
                                    <div class="title">Preço Base</div>
                                    <div class="duration">x
                                    <?php
                                    $diff= date_diff($entrada,$saida);
                                    echo $diff->format("%a noites");
                                    ?>
                                    </div>
                                </td>
                                <td class="price"><?php echo $regx['preco'];?>€</td>
                            </tr>
                            <tr>
                                <td>
                                    <div class="title">Total</div>
                                    <div class="duration"><?php echo $diff->format("%a noites")?></div>
                                </td>
                                <td class="price"><?php echo $regx['preco']*$diff->format("%a noites") ;?>€</td>
                            </tr>
                        </table>
                    </div>
                </div>
            </div>
       </form>
    </div>
<?php
}
?>