How to display data from db in select list [closed]

You’re recreating the select element on every iteration through the loop, and you need to name your current loop assignment variable differently, as you’re overwriting your original.

Lastly, you’re also not assigning a value to the options within the loop, so you’re not going to get anything on the form submission, and text isn’t a valid type for a select element.

Try this:

global $wpdb;
$results = $wpdb->get_results ("SELECT adres FROM wp_ow_adres;");
echo '<td><select id="adres" name="adres">';
echo '<option value="">Select your address</option>';
foreach ( $results as $result ) {
    echo '<option>'.$result->adres.'</option>';
}
echo </select></td>';

FYI, this is technically off topic for this site as it’s a php issue rather than a WordPress one, it just happens in the “context” of WordPress.