Detta fungerade också, det är en modifiering av janlindos ovan
<div class="form-group">
Select Make <?php
include '../db_config/dbcon.php';
$sql = "SELECT * FROM vehicle_details";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<select name='vehicle_make'>";
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<option value='" . $row['vehicle_make'] . "'>" . $row['vehicle_make'] . "</option>";
}
echo "</select>";
}
?>
</div>