带有数据库下拉菜单的PHP开关

我试图在交换机中包含一个下拉菜单（动态的，由数据库提供动力），但不知道如何。。有人做过类似的事情吗

<?php
$favcolor = "red";

switch ($favcolor) {
    case "red":
        echo "Your favorite color is red!";
        echo "<select>
            $query = mysqli_query($conn, "SELECT Spessore FROM spessori");
            while($row = mysqli_fetch_assoc($query)){
                <option>echo $row['Spessore'];</option>
                }
              </select>
        break;
         case "blue":
        echo "Your favorite color is blue!";
        break;
    case "green":
        echo "Your favorite color is green!";
        break;
    default:
        echo "Your favorite color is neither red, blue, nor green!";
    }
?>

---

您以错误的方式使用了
echo
。将其用作：

    echo "<select>";
        $query = mysqli_query($conn, "SELECT Spessore FROM spessori");
        while($row = mysqli_fetch_assoc($query)){
            echo "<option>". $row['Spessore'] ."</option>";
             }
    echo "</select>";

echo”“；
$query=mysqli_query（$conn，“从spessori中选择Spessore”）；
while（$row=mysqli\u fetch\u assoc（$query））{
回显“$row['Spessore']”；
}
回声“；

您应该了解，HTML标记在PHP中不起作用