gistfile1.phtml

<?php

$sql = "SELECT * FROM custom_info ORDER by cust_name";
$query = mysqli_query($conn, $sql);
echo "<form action='index4a.php' method='get'>"; 
echo "<select name='customer'>";
echo "<option value=''>Customer</option>";
while($customer = mysqli_fetch_assoc($query)){
echo "<option value='{$customer['cust_name']}'> {$customer['cust_name']}</option>";
}
echo "</select>";
echo "<input type='submit'/>";
echo "</form>";