问在SQL查询之后，我不知道结果来自哪里

EN

    //enquire price
if(isset($_POST["postcode_suburb"])) {
$postcode_suburb = $_POST["postcode_suburb"];
$postcode=substr($postcode_suburb, 0, 4);
$suburb=substr($postcode_suburb, 5);
$query = 
"SELECT wp_8jhcgrrzks_city_detail.postcode,wp_8jhcgrrzks_city_detail.city_name,wp_8jhcgrrzks_distribution_zone.distribution_zone_name, wp_8jhcgrrzks_distribution_zone.plan_page_id FROM wp_8jhcgrrzks_distribution_zone 
INNER JOIN wp_8jhcgrrzks_city_detail ON wp_8jhcgrrzks_city_detail.distribution_zone_id = wp_8jhcgrrzks_distribution_zone.distribution_zone_id 
WHERE wp_8jhcgrrzks_city_detail.postcode='".$postcode."' AND wp_8jhcgrrzks_city_detail.city_name='".$suburb."'";
$page_id;
if ($result = $mysqli->query($query)) {

    /* fetch object array (THIS IS THE PART I DON'T UNDERSTAND */

    while ($obj = $result->fetch_object()) {
        $page_id = $obj->plan_page_id;
    }
$parse_uri = explode( 'wp-content', $_SERVER['SCRIPT_FILENAME'] );
require_once( $parse_uri[0] . 'wp-load.php' );
  WPBMap::addAllMappedShortcodes();

    global $helmets;

    $post_id = get_post($page_id);
    $content = $post_id->post_content;
    $content = apply_filters('the_content', $content);
    $content = str_replace(']]>', ']]>', $content);
    echo do_shortcode($content);