MySQL Procedure displaying random banner at nixmash.com

p_current_site_image_get

CREATE PROCEDURE `p_current_site_image_get`()
BEGIN
    DECLARE existing_site_image_id BIGINT;
    DECLARE new_site_image_id BIGINT;
    DECLARE active_image_count INT;
    DECLARE random_number INT;

    SELECT site_image_id
    INTO existing_site_image_id
    FROM site_images
    WHERE is_current = 1 AND day_of_year = DAYOFYEAR(NOW());

    IF existing_site_image_id IS NULL
    THEN

      UPDATE site_images
      SET is_current = 0, day_of_year = DAYOFYEAR(NOW());

      SELECT count(*)
      INTO active_image_count
      FROM site_images
      WHERE is_active = 1 AND banner_image = 1;

      CREATE TEMPORARY TABLE t_site_images (
        id INT AUTO_INCREMENT PRIMARY KEY,
        site_image_id BIGINT NOT NULL,
        is_current TINYINT(1) DEFAULT 0
      );

      INSERT INTO t_site_images (site_image_id) SELECT site_image_id
                                FROM site_images
                                WHERE is_active = 1 AND banner_image = 1;

      SELECT FLOOR(RAND() * active_image_count) INTO random_number;
      UPDATE t_site_images SET is_current = 1 WHERE id = random_number + 1;

      SELECT site_image_id INTO new_site_image_id FROM t_site_images WHERE is_current = 1;
      UPDATE site_images SET is_current = 1 WHERE site_image_id = new_site_image_id;

      DROP TABLE t_site_images;
    END IF;

   SELECT * from site_images where is_current = 1 LIMIT 1;

  END