Comment 1 for bug 1011543

Trigger example:

DELIMITER $$

USE `banktest`$$

DROP TRIGGER /*!50032 IF EXISTS */ `sales_update`$$

CREATE
    /*!50017 DEFINER = 'root'@'localhost' */
    TRIGGER `sales_update` AFTER UPDATE ON `sales`
    FOR EACH ROW BEGIN
 IF NOT OLD.id_parent <=> NEW.id_parent THEN
  /*find all records for which the vertices of underlying referenced above, facing the top and remove them */
  DELETE sales_tree_p t1 FROM sales_tree_p t1
   JOIN (SELECT * FROM sales_tree_p WHERE id_sale_in = OLD.id_sale) t2 ON t2.id_sale = t1.id_sale
   JOIN (SELECT * FROM sales_tree_p WHERE id_sale = OLD.id_parent) t3 ON (t3.id_sale_in = t1.id_sale_in);
  /* calculate new values for the pair of underlying vertices and add them to the table */
  INSERT INTO sales_tree_p (id_sale, id_sale_in)
   SELECT t1.id_sale, t2.id_sale_in FROM sales_tree_p t1
   JOIN (SELECT * FROM sales_tree_p WHERE id_sale = NEW.id_parent) t2
   WHERE t1.id_sale_in = OLD.id_sale;
  /* maybe used for OQGRAPH
  update mega_test set origid = NEW.id_sale, destid = NEW.id_parent
   WHERE origid = OLD.id_sale AND destid = OLD.id_parent; */
 END IF;
END;
$$

DELIMITER ;