$wpdb->update("wp_table",
                array( 'content' => $html ),
                array( 'id' => 1 ),
                array( '%s' ),
                array( '%d' )
);

$wpdb->update("wp_sn_cached_popular_display",
                array( 'content' => "hello" ),
                array( 'id' => 1 ),
                array( '%s' ),
                array( '%d' )
);

$string = "hello";

$wpdb->update("wp_sn_cached_popular_display",
                array( 'content' => $string),
                array( 'id' => 1 ),
                array( '%s' ),
                array( '%d' )
);

$html .= '<li>';
$html .= '<div class="upcoming-left">';
$html .= '<time datetime="' . $date . '" class="icon">';
$html .= '<em>' . $date_day.'</em>';
$html .= '<strong>' . $date_month . '</strong>';
$html .= '<span>' . $date_num . '</span>';
$html .= '</time>';
$html .= '</div>';
$html .= '<div class="upcoming-right">';
$html .= '<span class="upcoming-title"><a href="' . $upcoming_link . '">' . $upcoming_title . '</a></span>';
$html .= '<span class="upcoming-desc">' . $upcoming_desc . '</span>';
$html .= '<div class="clear:both;"></div>';
$html .= '</div>';
$html .= '</li>';
//...