Display San Francisco Bay Area for IPV4

/****************************************************************************************************************/
/* Description: This snippet is provide simple way to help user display San Francisco Bay Area .                */
/*              suggestions for different city locations across the country.                                    */
/*              There are 1 steps in this snippet. For information, please visit IP2Location tutorial page at:  */
/* https://www.ip2location.com/tutorials/display-san-francisco-bay-area                                         */
/****************************************************************************************************************/
/* You can obtain free IP2Location LITE database for IPv4 at https://lite.ip2location.com                       */
/* You can obtain free Bay Area CSV file form Github at https://github.com/chrislim2888/bay-area                */

<?php
    if(isset($_POST['ip_address'])){
    $conn = new mysqli("localhost", "root", "", "sf_bay");
    if (mysqli_connect_errno()) {
        echo "<p>Connection failed:".mysqli_connect_error()."</p>\n";
    }

    $ip = $_POST['ip_address'];

    $sql = "SELECT db.country_name, db.region_name, db.city_name, b.bay_area
    FROM ip2location_db3 db, bay_area b
    WHERE db.region_name = b.region_name
    AND db.country_code = b.country_code
    AND inet_aton('$ip') <= db.ip_to
    limit 1";

    $result = mysqli_query($conn, $sql) or die (mysqli_error($conn));

    mysqli_close($conn);
    }
    ?>
    <!DOCTYPE html>
    <html>
    <head>
        <title>San Francisco Bay Areas</title>
        <style>
            th, td{
                padding-right: 15px;
                text-align: left;
            }
        </style>
    </head>

    <body>
        <h2>San Francisco Bay Areas</h2>
        <p>Enter an IP address to extract bay area information</p>
        <form name="query" method="post">
            <label for="address">IP here: </label>
            <input type="text" name="ip_address" id="ip_address" size="40" value="<?= isset($_POST['ip_address']) ? htmlspecialchars($_POST['ip_address']) : '' ?>">
            <button type="submit">Run</button>
        </form>
        <br/>
        <table>
        <tr>
            <th>Country</th>
            <th>Region</th>
            <th>City</th>
            <th>Bay Area</th>
        </tr>
        <?php
        if (isset($ip)){
            while ($row = mysqli_fetch_assoc($result)){
                $country = $row['country_name'];
                $region = $row['region_name'];
                $city = $row['city_name'];
                $bay = $row['bay_area'];
                echo "<tr>";
                echo "<td>".$country."</td>";
                echo "<td>".$region."</td>";
                echo "<td>".$city."</td>";
                echo "<td>".$bay."</td>";
                echo "</tr>";
            }
            echo "</table>";
        }
    ?>

    </body>
    </html>