如何使用POST方法从数据库中获取带有选项的选择输入标记的值 - How to get a value of a select input tag with options taken from a database using POST method?

How to get a value of a select input tag with options taken from a database using POST method?

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <select name="doctor">
    <?php 
    $con = mysqli_connect("---","---","---","---") or die("Can't Connect to the Database.");
    $sql = mysqli_query($con, "SELECT Title, Name, LastName FROM physician");
    while ($row = $sql->fetch_assoc()){
    echo "<option value='"doctor1'">" . $row['Title'].' '.$row['Name'].' '.$row['LastName'] . "</option>";
    }
    ?>
    </select>
    &nbsp;<input type='submit' value="Filter"><br>
</form>

上面是我创建的一个表单。我使用POST方法。这个表单有一个选择输入标签，它的选项是从我的数据库。当表单提交时，我需要访问用户使用$_POST['doctor']函数选择的值。但它没有给我任何值。有人能帮我吗?

如果"physician"表中每个条目的ID存储在" physicanid "列中，则应该尝试以下代码片段:

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
    <select name="doctor">
        <?php 
            $con = mysqli_connect("---","---","---","---") or die("Can't Connect to the Database.");
            $sql = mysqli_query($con, "SELECT PhysicianID, Title, Name, LastName FROM physician");
            while ($row = $sql->fetch_assoc()){
                echo '<option value="'.$row['PhysicianID'].'">'.$row['Title'].' '.$row['Name'].' '.$row['LastName'].'</option>';
            }
        ?>
    </select>
    &nbsp;<input type='submit' value="Filter"><br>
</form>