Retrieving dropdown options out of a database - php

Question

I want to create a dropdown filled with numbers. These numbers need to be retrieved from a database. The connection to the database and the supposed display code are as follows:
The Function to retrieve the options for the dropdown
<?php
function dropdown_menu() {
global $wpdb;
/* Query the database */
$query = $wpdb->prepare('SELECT * FROM LID ORDER BY LidID', 'LID', 'LidID');
$results = $wpdb->get_results($query);
/* Check for $results */
if(!empty($results)) :
/* Loop through the $results and add each as a dropdown option */
global $options;
$options = '';
foreach($results as $result) :
echo ("<option value=\"<?php echo $item->LidID ?>\"> <?php echo $item->LidID ?> </option>");
endforeach;
endif;
}
?>
The statement which includes the aforementioned function into a form:
<tr class="form-field form-required">
<th scope="row"><label for="LidID">Lid ID <span class="description">(verplicht)</span></label></th>
<td><select name="LidID" id="LidID" value="<?php echo $item->LidID ?>" aria-required="true"> <?php dropdown_menu(); ?> </select></td>
</tr>
The problem I'm having, is that it creates a dropdown list with the corresponding amount of records of "LidID" in the database, but they all show up blank. I've already been toying around with it, and I think I know what the problem is, but I don't know how to solve it. I presume the problem lies within the echo-statement;
echo ("<option value=\"<?php echo $item->LidID ?>\"> <?php echo $item->LidID ?> </option>");
when I remove the second LidID ?> and replace it with, for example, a 5, it shows a list of fives. For some reason it doesn't recognize the statement I wrote. I've tried to switch out both the $item->LidID in the echo statement into $result->LidID, but that doesn't seem to have any impact. Does anyone have the slightest idea of what is going wrong here?
Oh yeah, I don't know if it's relevent but it's a plug-in for wordpress.

Answer 1

You're right, that is the issue. You are already in PHP when echoing, so you don't need to open more PHP tags. The other issues is $item doesn't exist. Another issue is you're not using MySQLi correctly, you only use prepare if you have a variable, you don't so don't use it. You also don't use get_results in that context. Try this:
function dropdown_menu($default) {
global $wpdb;
/* Query the database */
$query = 'SELECT * FROM LID ORDER BY LidID, LID, LidID';
$results = $wpdb->query($query);
while ($item = $results->fetch_assoc()):
echo '<option value="'.$item->LidID.'"'.($item->LidID == $default ? ' selected="selected"' : '').'>'.$item->LidID.'</option>';
endwhile;
}
Then when calling the function
<td>
<select name="LidID" id="LidID" aria-required="true"> <?php dropdown_menu($item->LidID); ?> </select>
</td>