my search box

//CUSTOM SEARCH BOX E SUO SHORTCODE
//CODICE GURU di WordPress Buddha

function wpb_demo_shortcode() {
    global $wpdb, $wp_query;

    // Retrieve categories dropdown
    $categories = wp_dropdown_categories([
        'show_count' => 1,
        'hierarchical' => 1,
        'show_option_all' => esc_html__('All destinations', 'sacconicase'),
        'echo' => false,
    ]);

    // Retrieve tipologia dropdown
    $select = $wp_query->get('tipologia');
    $select = '' == $select ? 0 : $select;
    $taxonomy = wp_dropdown_categories([
        'hierarchical' => false,
        'name' => 'tipologia',
        'taxonomy' => 'tipologia',
        'selected' => $select,
        'show_option_all' => esc_html__('Typology', 'sacconicase'),
        'value_field' => 'slug',
        'echo' => false
    ]);

    // Retrieve unique values for 'function_camere' custom field
    $functionCamereValues = $wpdb->get_col("SELECT DISTINCT meta_value FROM $wpdb->postmeta WHERE meta_key = 'function_camere' ORDER BY meta_value");
    $functionCamereDropdown = '<select name="function_camere">';
    $functionCamereDropdown .= '<option value="">' . esc_html__('n.Bedrooms', 'sacconicase') . '</option>';
    foreach ($functionCamereValues as $value) {
        $functionCamereDropdown .= '<option value="' . esc_attr($value) . '">' . esc_html($value).'+' . '</option>';
    }
    $functionCamereDropdown .= '</select>';

// Retrieve unique values for 'function_ospiti' custom field
    $functionOspitiValues = $wpdb->get_col("SELECT DISTINCT meta_value FROM $wpdb->postmeta WHERE meta_key = 'function_ospiti' ORDER BY meta_value");
    $functionOspitiDropdown = '<select name="function_ospiti">';
    $functionOspitiDropdown .= '<option value="">' . esc_html__('n.Guests', 'sacconicase') . '</option>';
    foreach ($functionOspitiValues as $value) {
        $functionOspitiDropdown .= '<option value="' . esc_attr($value) . '">' . esc_html($value).'+' . '</option>';
    }
    $functionOspitiDropdown .= '</select>';



    // Form output
    $output = '<form class="sacconi_form" method="get" action="' . home_url('/') . '">' .
              $categories . $taxonomy . $functionOspitiDropdown . $functionCamereDropdown . '<br><br>' .
              '<input type="submit" name="search" value="' . esc_html__('Search', 'sacconicase') . '">' .
              '</form>';

    return $output;
  }


// register shortcode

add_shortcode('ricerca', 'wpb_demo_shortcode');