SimpleHistory::get_unique_events_for_days PHP Method

    public function get_unique_events_for_days($days = 7)
    {
        global $wpdb;
        $days = (int) $days;
        $table_name = $wpdb->prefix . SimpleHistory::DBTABLE;
        $cache_key = "sh_" . md5(__METHOD__ . $days);
        $numEvents = get_transient($cache_key);
        if (false == $numEvents) {
            $sql = $wpdb->prepare("\n\t\t\t\tSELECT count( DISTINCT occasionsID )\n\t\t\t\tFROM {$table_name}\n\t\t\t\tWHERE date >= DATE_ADD(CURDATE(), INTERVAL -%d DAY)\n\t\t\t", $days);
            $numEvents = $wpdb->get_var($sql);
            set_transient($cache_key, $numEvents, HOUR_IN_SECONDS);
        }
        return $numEvents;
    }