从SQL数据库中选择值并显示在下拉列表中，提交表单

Question

The values from the db are displaying in the dropdown and I've gotten it to work with text values that weren't pulled from the db, but when I try it with values from the db and click 'Submit' the page reloads and nothing happens.

My code:

<form action="test.php" method="post">
<br />
<label for="name">Choose a name</label><br />

 <select name="selected_value">
 $query = "SELECT * FROM items WHERE user_id = $user_id";
 $select_items = mysqli_query($connection, $query);
 confirmQuery($select_items);
 while($row = mysqli_fetch_assoc($select_items)) {
 $item_id = $row['item_id'];
 $item_name = $row['item_name'];
 echo "<option value='$item_name'>{$item_name}</option>";

 </select>
 <button type="submit" name="submit_form">Submit</button>
 </form>


 if(isset($_POST['submit_form'])){
 $selected_value = $_POST['selected_value'];
 echo $selected_value;
 }

Answer 1

Don't you have this the wrong way around?

$_POST['selected_value'] = $selected_value;

should be

$selected_value = $_POST['selected_value'];