How to make query switch variables if row not found in php and sql

Question

I have a form for real estate search and the first field should be able to return result based on 3 fields in the database. if by hood returns 0 then it should search by city else search by country

  <?php


    //search value
    $location=$_GET["location"];
    $type=$_GET['type'];
    $price=$_GET['price'];


    //==================================================================

    #variables of search query
    // User input
    $page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
    $perPage = isset($_GET['per-page']) && $_GET['per-page'] <= 50 ? (int)$_GET['per-page'] : 6;

    // Positioning
    $start = ($page > 1) ? ($page * $perPage) - $perPage : 0;

    // Query
    $articles = "
        SELECT SQL_CALC_FOUND_ROWS property_id, title,bedrooms,images,owner,status,posted_by,gsize,city,price,post_date,location,currency,poster_id
        FROM properties where location='$location' or city='$location' or hood='$location'
    ";


            if($type && !empty($type)){

           $articles .= " AND property_type='$type'";
            }

            if($price && !empty($price)){
                $articles .=" AND price <= '$price'";
            }

                    $articles .= " order by post_date desc LIMIT {$start}, {$perPage}";

                    $articles=$dbc->query($articles);

    $articles = $articles->fetchAll(PDO::FETCH_ASSOC);


    ?>